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Microsoft Defender for Office 365 vs Retarus Email Security comparison

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Comparison Buyer's Guide

Executive Summary

Review summaries and opinions

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

Categories and Ranking

Microsoft Defender for Offi...
Ranking in Secure Email Gateway (SEG)
2nd
Average Rating
8.4
Reviews Sentiment
6.8
Number of Reviews
61
Ranking in other categories
Email Archiving (2nd), Email Security (2nd), Advanced Threat Protection (ATP) (3rd), Microsoft Security Suite (8th)
Retarus Email Security
Ranking in Secure Email Gateway (SEG)
16th
Average Rating
8.0
Reviews Sentiment
5.6
Number of Reviews
1
Ranking in other categories
No ranking in other categories
 

Mindshare comparison

As of November 2026, in the Secure Email Gateway (SEG) category, the mindshare of Microsoft Defender for Office 365 is 12.4%, down from 27.6% compared to the previous year. The mindshare of Retarus Email Security is 1.2%, up from 0.5% compared to the previous year. It is calculated based on PeerSpot user engagement data.
Secure Email Gateway (SEG) Mindshare Distribution
ProductMindshare (%)
Microsoft Defender for Office 36512.4%
Retarus Email Security1.2%
Other86.4%
Secure Email Gateway (SEG)
 

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.
WAKKAS AHMAD - PeerSpot reviewer
Security Consultant at Mahle
Provides valuable reports that make it easy to take action
Our primary use case for this solution is protecting emails This solution has helped our organization by protecting our emails from various threats. It helped us get customized reports on all of the emails we received on the user side and other data. The feature I found most valuable was getting…

Quotes from Members

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

Pros

"The most valuable feature is the integration; it's a single console, so we don't have to switch around between multiple products, and another valuable feature is the ease of operations and maintenance."
"Defender for 365 is a comprehensive cloud-based solution. The value of the cloud is that you aren't alone. Threat intelligence and analytics are shared in the cloud. We don't have to find the solution alone. If you face an unknown threat with traditional solutions like Trend Micro and Symantec, you need to open a case and send your information to them to analyze forensically and identify the source of the attack."
"Microsoft Defender for Office 365 saves me time; it does save a lot of time, especially with the automation."
"The product's scalability is good."
"Defender enables us to secure all 365-related activity from a single place. It gives us visibility into everything happening in Outlook, protecting us against phishing and other email-based threats. Defender helps us detect any suspicious behaviors."
"My experience deploying Microsoft Defender for Office 365 was seamless."
"It has significantly decreased my time to detection and response."
"Our customers are satisfied with Defender for 365 because Microsoft products are easy to use and customize to meet the client's needs. Everything is in one place, so we can adjust policies as needed for phishing, DLP, ATP, or any other security features that our clients want to apply."
"The feature I found most valuable was getting details on the emails, being alerted once those emails got a bad reputation, and then being able to take action on those emails."
 

Cons

"If you look at other products, such as Wiz or Palo Alto's cloud, because they also have similar components in terms of how they protect cloud infrastructure or enable cloud security, Microsoft Defender for Office 365 is not up to that extent."
"Microsoft Defender for Office 365 should improve the troubleshooting tools. It's unclear whether the device is blocked at the firewall level or at the device itself. The granularity needed for troubleshooting is currently lacking. From my perspective, Microsoft should address this issue to benefit many users who likely share the same sentiment."
"There is room for improvement in terms of reporting."
"Microsoft Defender for Office 365 should be more proactive."
"The UI needs to be more user-friendly."
"Configuring the default strategies and policies in Microsoft Defender for Cloud Apps generates a lot of noise and false positives."
"The cost of Security Copilot is up there right now, and I think it needs to come down for more people to adopt."
"Microsoft sometimes has downtime, and we'll get several incidents coming in back to back. We have a huge backlog of notifications, many of which may be false positives. However, there might be serious alerts, so we can't risk dismissing all of them at once."
"This solution needs to improve the area of GUI as well as dashboards because they are very poor in terms of the current email security solution."
 

Pricing and Cost Advice

"The license is expensive because the cost is based on the number of users."
"The pricing has become expensive."
"Defender is a little bit more expensive as compared to others. We are in the manufacturing environment. So, we don't have a high budget for all of our endpoint devices. Its cost is a major concern for us."
"For licensing, it's usually a yearly package for customers who are subscribed to Office 365, but they can also pay on a monthly basis."
"The pricing is normal. Considering its popularity, it's not overpriced."
"From the pricing point of view, like any other product in the market, there is scope for negotiation."
"The product is very expensive."
"Defender for 365 comes in various plans and licenses, along with other Microsoft security solutions. Purchasing this kind of package or security bundle gives good value for money, and that's what I recommend."
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Top Industries

By visitors reading reviews
Computer Software Company
11%
Manufacturing Company
10%
Financial Services Firm
8%
Comms Service Provider
7%
No data available
 

Company Size

By reviewers
Large Enterprise
Midsize Enterprise
Small Business
By reviewers
Company SizeCount
Small Business24
Midsize Enterprise11
Large Enterprise32
No data available
 

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 competitor...
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.
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Also Known As

MS Defender for Office 365
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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 Proofpoint, Microsoft, Mimecast and others in Secure Email Gateway (SEG). Updated: October 2026.
921,523 professionals have used our research since 2012.