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

Heimdal Email Security vs Microsoft Defender for Office 365 comparison

Sponsored
 

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

Cloudflare One
Sponsored
Ranking in Email Security
20th
Average Rating
8.6
Reviews Sentiment
6.5
Number of Reviews
23
Ranking in other categories
Secure Web Gateways (SWG) (13th), Data Loss Prevention (DLP) (20th), Cloud Access Security Brokers (CASB) (12th), Distributed Denial-of-Service (DDoS) Protection (7th), Software Defined WAN (SD-WAN) Solutions (12th), Access Management (11th), Bot Management (3rd), ZTNA as a Service (9th), ZTNA (4th), Secure Access Service Edge (SASE) (10th), Remote Browser Isolation (RBI) (3rd)
Heimdal Email Security
Ranking in Email Security
59th
Average Rating
9.0
Reviews Sentiment
7.9
Number of Reviews
1
Ranking in other categories
Fraud Detection and Prevention (56th)
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) (2nd), Microsoft Security Suite (8th), Secure Email Gateway (SEG) (1st)
 

Mindshare comparison

As of May 2026, in the Email Security category, the mindshare of Cloudflare One is 1.7%, up from 1.6% compared to the previous year. The mindshare of Heimdal Email Security is 0.4%, up from 0.2% compared to the previous year. The mindshare of Microsoft Defender for Office 365 is 6.9%, down from 12.9% compared to the previous year. It is calculated based on PeerSpot user engagement data.
Email Security Mindshare Distribution
ProductMindshare (%)
Microsoft Defender for Office 3656.9%
Cloudflare One1.7%
Heimdal Email Security0.4%
Other91.0%
Email Security
 

Featured Reviews

CV
Network Architect at IP Dimension
Cloud security has improved remote access and has reduced costs for smaller client sites
I have used Cloudflare One's Identity-Aware Proxy, and it is quite straightforward from what I have seen so far. The app registration on the Azure side integrates fully into Cloudflare, and I am very satisfied with that part because it is easy to set up. The integration of Cloudflare One's Secure Web Gateway and Zero Trust Network Access works without any issues. That part is pretty automatic, and if you complete the rest of the setup, it comes together by itself with no issues from my side. What makes it nice is that we can actually start replacing on-site firewalls at this stage for the smaller clients because it does not matter if they go to a coffee shop or work from home; they are still secured by the same connection. The hops get shorter and you get better latency. We have done testing to see if it is better. One thing that we did notice with our proof of concept with our current client is that they have people connecting from the UK. When they used their previous VPN solution, uploading CAD drawings and other files to the server took a long time. They mentioned that it is much quicker on Cloudflare One's solution. I definitely believe that is part of the improved performance, and I am satisfied with that as well. What is nice about Cloudflare One is that it makes the setup easier and also easier to train technicians to maintain it. Compared to legacy systems, we do not need to get fancy firewalls in place that are costly. That is definitely also a cost-saver with Cloudflare One.
Melvin Ong - PeerSpot reviewer
Country Manager at PT Symcaw Solutions Indonesia
Straightforward to set up, reliable, and offers good functionality
We primarily use the solution for email security and general email management.  It's improved our productivity.  The solution works well overall. The functionality is very good.  The setup process is easy.  It is stable and reliable. It's scalable.  I don't have any specific areas that need…
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.

Quotes from Members

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

Pros

"Cloudflare DDoS mitigates DDoS attacks."
"The tool also offers good scalability, and the dashboard, along with real-time analytics, is very good."
"Cloudflare is simple to use."
"The blocking feature is very good."
"I'm very satisfied with the environment and the dashboard."
"It will take the blow rather than our applications should an attack occur."
"The simplicity of the solution is its valuable features as almost no effort was needed to learn the configurations. It is also one of the cheapest firewalls available in this category."
"Enables me to work from two locations."
"It is stable and reliable."
"The DLP feature of Microsoft Defender for Office 365 is valuable, and we also use the DLP feature for email real-time detection."
"With Defender for Office 365, we have been able to increase the security posture across our organization."
"Microsoft Defender for Office 365 facilitates efficient management and updates through the cloud. We do not have to worry about incompatibilities. It just works."
"There are several features that I consider valuable."
"Overall, I would rate Microsoft Defender for Office 365 at a ten."
"Safe attachments, safe links, policies, and the ability to protect from zero-day threats are the most valuable features."
"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."
"My experience deploying Microsoft Defender for Office 365 was seamless."
 

Cons

"The pricing is an area that can be improved. Pricing, as far as I recall, was the source of our problems."
"Feedback could be enhanced. While I work efficiently with Clover as a partner in Mexico City, sometimes the information and requests are easier to manage with more concrete solutions."
"The initial onboarding was causing us some confusion."
"For the topic of improvement, providing some training material is one of my suggestions."
"Our subscription plan for the solution has a limitation of bot signatures."
"Lacks a VPN feature to provide a secure connection to the data center."
"Cloudflare DDoS has poor technical support."
"Cloudflare Zero Trust Platform needs to improve its documentation. It took time to do the implementation."
"The solution could be less expensive."
"There is room for improvement in terms of reporting."
"The inbuilt analysis of false positives can be faster. It's not slow, but it can be faster."
"We need to be able to whitelist data at the backend."
"In one of the reports I can get the exact place where a vulnerable file resides. But for that, I need to explicitly go into the device and check. If they could include that file part in the report, without my having to go to the device itself, that would help."
"We are waiting for better software to block viruses."
"Sometimes, phishing emails manage to pass through the filter, so the system needs to enhance its phishing email detection capabilities."
"The changes to customer service, specifically the new model for support agreements, are not favorable."
"I assess the stability and reliability of the solution as seven out of ten."
 

Pricing and Cost Advice

"Cloudflare Zero Trust Platform's pricing is good."
"The solution's pricing lacks transparency."
"The prices are slightly expensive."
"The price tag is no longer $200,000, but rather $300,000 to $400,000. It's twice."
"My company has to make yearly payments towards the licensing costs attached to the solution. There are no hidden charges apart from the licensing costs of the solution."
"The solution is not that expensive."
"The pricing of the solution is cheap. The licensing cost is also very low. I rate the cost and pricing a three out of ten."
"The pricing is somewhere in the middle. I would rate the pricing a seven out of ten."
Information not available
"Microsoft Defender for Office 365 comes with Microsoft Windows. It is free with the operating system."
"For large enterprise organizations, they can definitely afford it, but for small and medium organizations, they might struggle to cover the expenses."
"The pricing has become expensive."
"From the pricing point of view, like any other product in the market, there is scope for negotiation."
"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 solution could be better by simplifying the business model of their licensing. It was hard to figure out how to get the licensing done for the environment, initially."
"I know that the product is incredibly expensive."
"The product is expensive."
report
Use our free recommendation engine to learn which Email Security solutions are best for your needs.
895,891 professionals have used our research since 2012.
 

Top Industries

By visitors reading reviews
Construction Company
20%
Comms Service Provider
11%
Financial Services Firm
9%
Manufacturing Company
6%
Construction Company
20%
Comms Service Provider
7%
Logistics Company
7%
Energy/Utilities Company
7%
Computer Software Company
12%
Financial Services Firm
9%
Manufacturing Company
8%
Comms Service Provider
7%
 

Company Size

By reviewers
Large Enterprise
Midsize Enterprise
Small Business
By reviewers
Company SizeCount
Small Business10
Midsize Enterprise1
Large Enterprise12
No data available
By reviewers
Company SizeCount
Small Business24
Midsize Enterprise12
Large Enterprise32
 

Questions from the Community

What needs improvement with Cloudflare Access?
Cloudflare Access has strong integration with Microsoft, among other platforms. However, when it comes to Kaspersky, ...
What is your primary use case for Cloudflare Access?
Cloudflare Access provides secure access to internal applications for employees, external members of the organization...
What advice do you have for others considering Cloudflare Access?
Cloudflare Access is one of the best integrations available. While about two hundred vendors offer similar services, ...
Ask a question
Earn 20 points
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...
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 ...
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.
 

Also Known As

Cloudflare Area 1 Email Security, Cloudflare Bot Management, Cloudflare Gateway, Cloudflare Zero Trust Platform, Cloudflare DDoS, Cloudflare SASE & SSE Platform
MailSentry
MS Defender for Office 365
 

Overview

 

Sample Customers

23andMe
Brother, Symbion, CPH West
Microsoft Defender for Office 365 is trusted by companies such as Ithaca College.
Find out what your peers are saying about Proofpoint, Microsoft, Check Point Software Technologies and others in Email Security. Updated: May 2026.
895,891 professionals have used our research since 2012.