No more typing reviews! Try our Samantha, our new voice AI agent.

Microsoft Defender for Office 365 vs Trellix Email Security comparison

 

Comparison Buyer's Guide

Executive SummaryUpdated on Jan 18, 2026

Review summaries and opinions

We asked business professionals to review the solutions they use. Here are some excerpts of what they said:
 

ROI

Sentiment score
7.1
Microsoft Defender for Office 365 boosts efficiency, cuts phishing, integrates security, reduces tool costs, and mitigates risk.
Sentiment score
6.4
Trellix Email Security cuts costs, boosts security, reduces incidents, and simplifies management, offering notable time-saving and ROI benefits.
It has also decreased our time to detection and response by about 15 to 20 percent.
Technology support manager at Alfred State College
Overall, cost of owning and operating our system goes down.
Designation Chief Consultant at Avtow
It's hard to quantify the return on investment we've seen from Microsoft Defender for Office 365.
Chief Architect at a tech vendor with 1,001-5,000 employees
It reduces costs by almost 40% or 45% compared to other security solutions.
Senior Technical Support Engineer at Digitaltrack
The question is what would happen if an organization did not have this security measure in place and got hit by ransomware.
Security Consultant at Trinexia
One of the main positive impacts of Trellix Email Security is its ability to detect and respond to phishing and suspicious email activity much faster.
Technical Business Analyst at a financial services firm with 10,001+ employees
 

Customer Service

Sentiment score
5.7
Microsoft Defender for Office 365 support is reliable but varies with subscription level and complexity of issues.
Sentiment score
5.7
Trellix Email Security's customer service is praised for quick responses but criticized for inconsistency and lengthy solution times.
Over the past two years, there have been no critical problems.
Solution Consultant at BIM Group of Companies
we opened tickets, and they typically resolve them quickly.
Chief Architect at a tech vendor with 1,001-5,000 employees
With a subscription for Microsoft Defender for Office 365, it is an eight. Without it, it is a six.
Manager at a tech services company with 10,001+ employees
Solutions take three to four weeks maximum if you want something fixed.
Associate Cybersecurity Analyst at a tech vendor with 10,001+ employees
Trellix should have a dedicated center for the African market due to the unique dynamics and challenges within this region.
Partner Account Manager at a consumer goods company with 11-50 employees
We raise a case on the customer portal, and our engineer will be aligned with us, and the engineer resolves the issue.
Security Engineer at itsipl
 

Scalability Issues

Sentiment score
7.8
Microsoft Defender for Office 365 efficiently scales with cloud-native design, ensuring reliable performance and seamless integration for diverse organizations.
Sentiment score
6.1
Trellix Email Security offers scalable cloud and on-premises solutions, efficiently handling large volumes and evolving business needs cost-effectively.
We have never faced scalability problems, and Microsoft manages it effectively.
Solution Consultant at BIM Group of Companies
Microsoft Defender for Office 365 scales transparently for us, as we grew from 1,000 users to 3,000 users, and we didn't notice much difference.
Chief Architect at a tech vendor with 1,001-5,000 employees
Microsoft Defender for Office 365 scales with the growing needs of my company well.
Senior Client Director and Advisory Service Leader at Crossfuze
The scalability rates at nine out of ten.
Senior Technical Support Engineer at Digitaltrack
I would rate scalability between eight and nine because Trellix Email Security can be deployed in the cloud or on-premises, and in terms of scale, it can handle any size.
Security Consultant at Trinexia
The scalability of Trellix Email Security is excellent.
Senior Soc Analyst at a consultancy with 11-50 employees
 

Stability Issues

Sentiment score
7.8
Microsoft Defender for Office 365 offers consistently reliable performance with minimal downtime, high user ratings, and manageable minor issues.
Sentiment score
8.3
Trellix Email Security is reliable and stable, with high satisfaction in performance despite minor encryption deployment issues.
I would rate the stability of Microsoft Defender for Office 365 as 10 over 10 because it's highly available, it works, and it does the job it is meant to do.
Cloud Solutions Architect at a tech services company with 201-500 employees
I have not experienced any downtime, crashes, or performance issues because of Defender.
Technology Associate at a financial services firm with 51-200 employees
The solution is stable, as we have been using it for the past two years.
Solution Consultant at BIM Group of Companies
In terms of product stability, I would rate Trellix Email Security between eight and nine because the solution is quite stable.
Security Consultant at Trinexia
Trellix Email Security is very stable, with no downtime noticed.
Team Manager at Ford
Whenever we deploy the product from the ePO console to that particular machine, it shows that the product is inactive.
Information Security Engineer at Nhq Distribution Ltd
 

Room For Improvement

Microsoft Defender for Office 365 needs improvements in usability, false positive reduction, phishing detection, scalability, and reporting capabilities.
Trellix Email Security needs improvements in pricing, usability, reporting, and support, plus enhanced features and refined processes.
The main area for improvement is simplifying the implementation and rollout process.
Infrastructure and Security Lead at Vedanta
Microsoft could improve by offering recommendations for domain spoofing attacks, especially scenarios where DNS records like SPF, DKIM, and DMARC are not properly published.
Solution Consultant at BIM Group of Companies
There is a different console for different things; I just want one consolidated console.
Senior Director, Security Architecture & Engineering at a leisure / travel company with 10,001+ employees
If they provide better customization options, it would be easier to understand everything in a single dashboard instead of navigating through dropdown menus to see reports.
Senior Technical Support Engineer at Digitaltrack
I think there is a high number of false positives that also need attention.
Team Manager at Ford
They want to get the actual report on that, why they are sending and which way they are sending these emails.
Information Security Engineer at Nhq Distribution Ltd
 

Setup Cost

Microsoft Defender for Office 365 is cost-effective with E5, costly standalone, requiring careful planning for subscription-based licensing.
Trellix Email Security is affordable, cost-effective, competitive against rivals, with minimal setup, user/mail-based licensing, and high satisfaction.
We've likely saved 30% of costs.
Designation Chief Consultant at Avtow
Money-wise, it is a part of the Office 365 suite, making it slightly more expensive compared to Trend Micro.
Infrastructure and Security Lead at Vedanta
Microsoft is quite affordable with a lot of features available for any size organization.
Solution Consultant at BIM Group of Companies
I am satisfied with the secure licensing cost because compared to other solutions, Trellix Email Security is cheaper and provides most features.
Senior Technical Support Engineer at Digitaltrack
In my case, it is somewhat cost-effective and affordable.
Team Manager at Ford
The licensing is per user.
Security Engineer at itsipl
 

Valuable Features

Microsoft Defender for Office 365 enhances security with AI-driven phishing detection and robust protection across Microsoft 365 services.
Trellix Email Security offers advanced AI detection, real-time scanning, and integration to enhance threat protection and email infrastructure security.
It ranks the threats and allows us to prioritize those hitting us the hardest, such as email threats.
Technology support manager at Alfred State College
It provides end-to-end visibility on email threats such as phishing, extending beyond Exchange Online Protection.
Solution Consultant at BIM Group of Companies
The value of the DLP feature is significant to us because we have internal data, sometimes sensitive, and the users may not always be aware of security and privacy, which might lead them to send out information mistakenly to external parties.
Chief Architect at a tech vendor with 1,001-5,000 employees
If users try to open links that have converted to phishing after some time, those need to be blocked.
Senior Technical Support Engineer at Digitaltrack
My experience with the malware analysis and quarantine features is that they are easy to manage and they have been very effective because we have been able to quarantine any suspicious emails or prevent any attempt before it affects our systems.
Team Manager at Ford
Monitoring and threat tracking in Trellix Email Security have the potential to reduce significantly the threats because I am able to review and analyze in real-time any potential threats to my environment and tackle them immediately.
Sr. Service Delivery Consultant at a consultancy with 201-500 employees
 

Categories and Ranking

Microsoft Defender for Offi...
Ranking in Email Security
2nd
Average Rating
8.4
Reviews Sentiment
6.8
Number of Reviews
61
Ranking in other categories
Email Archiving (1st), Advanced Threat Protection (ATP) (3rd), Microsoft Security Suite (9th), Secure Email Gateway (SEG) (2nd)
Trellix Email Security
Ranking in Email Security
15th
Average Rating
8.8
Reviews Sentiment
6.2
Number of Reviews
13
Ranking in other categories
No ranking in other categories
 

Mindshare comparison

As of August 2026, in the Email Security category, the mindshare of Microsoft Defender for Office 365 is 5.7%, down from 11.6% compared to the previous year. The mindshare of Trellix Email Security is 0.4%, up from 0.1% compared to the previous year. It is calculated based on PeerSpot user engagement data.
Email Security Mindshare Distribution
ProductMindshare (%)
Microsoft Defender for Office 3655.7%
Trellix Email Security0.4%
Other93.9%
Email Security
 

Featured Reviews

Emeka Ndulu - PeerSpot reviewer
Cloud Solutions Architect at a tech services company with 201-500 employees
Improves threat visibility and response while reducing manual tasks and training users against phishing
I appreciate the attack simulation feature whereby I get to train users and educate them on how to identify phishing emails and spam emails, as well as the anti-spam protection. It gives me visibility into my threat environment and threat landscape to ensure that I am one step ahead of any likelihood of threats within my environment. I get to detect it and respond, so the threat intelligence is very effective. Microsoft security solutions save my time. It saves money because once I protect my environment, I don't lose money. It has decreased my detection time and my time to respond.
Anastasia Wairimu - PeerSpot reviewer
Team Manager at Ford
Gateway filtering has protected our organization and provides complete email threat prevention
In my opinion, the best features Trellix Email Security offers include its use for malware analysis as well as the enterprise-wide email quarantine system. My experience with the malware analysis and quarantine features is that they are easy to manage and they have been very effective because we have been able to quarantine any suspicious emails or prevent any attempt before it affects our systems. It is also very user-friendly and has a simple interface. Policies and rules are easy to create and they work with very little downtime or operational impact. Email delivery issues are easy to investigate and troubleshoot. Trellix Email Security has positively impacted my organization as it is user-friendly and does a good job detecting malicious attachments in email, providing complete email protection against all users and working well to stop advanced threats. The price is relatively the same as other competitors.
report
Use our free recommendation engine to learn which Email Security solutions are best for your needs.
909,725 professionals have used our research since 2012.
 

Top Industries

By visitors reading reviews
Computer Software Company
11%
Manufacturing Company
9%
Financial Services Firm
9%
Comms Service Provider
7%
Construction Company
14%
Computer Software Company
11%
Financial Services Firm
11%
Outsourcing Company
11%
 

Company Size

By reviewers
Large Enterprise
Midsize Enterprise
Small Business
By reviewers
Company SizeCount
Small Business24
Midsize Enterprise11
Large Enterprise32
By reviewers
Company SizeCount
Small Business9
Midsize Enterprise4
Large Enterprise7
 

Questions from the Community

What is your experience regarding pricing and costs for Microsoft Defender for Office 365?
My experience with pricing, setup, and licensing is that it's actually quite reasonable even on the licensing side as a standalone product. It's very competitive compared to what competitors are ch...
What needs improvement with Microsoft Defender for Office 365?
I think Microsoft Defender for Office 365 can be improved by creating more educational pieces about not just looking for malware. We are seeing a lot more malware-less emails that Defender for Offi...
What is your primary use case for Microsoft Defender for Office 365?
My main use cases for Microsoft Defender for Office 365 include email hygiene.
What is your experience regarding pricing and costs for Trellix Email Security?
My experience with pricing, setup cost, and licensing for Trellix Email Security is that everything good has a price. When we look at the cost relative to what it secures, I think that is acceptabl...
What needs improvement with Trellix Email Security?
Trellix Email Security can be improved in several areas. Although it has almost all the features that an email security tool should have, it could advance further with different types of attacks th...
What is your primary use case for Trellix Email Security?
My main use case for Trellix Email Security is for external communication, where we use the IOCs that we already have for phishing domains to capture phishing emails. For internal emails and outbou...
 

Also Known As

MS Defender for Office 365
No data available
 

Overview

 

Sample Customers

Microsoft Defender for Office 365 is trusted by companies such as Ithaca College.
Information Not Available
Find out what your peers are saying about Microsoft Defender for Office 365 vs. Trellix Email Security and other solutions. Updated: August 2026.
909,725 professionals have used our research since 2012.