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Heimdal Email Security vs Microsoft Defender for Office 365 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

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) (12th), Data Loss Prevention (DLP) (22nd), Cloud Access Security Brokers (CASB) (12th), Distributed Denial-of-Service (DDoS) Protection (8th), Software Defined WAN (SD-WAN) Solutions (13th), Access Management (12th), Bot Management (3rd), ZTNA as a Service (8th), ZTNA (4th), Secure Access Service Edge (SASE) (9th), Remote Browser Isolation (RBI) (2nd)
Heimdal Email Security
Ranking in Email Security
57th
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) (3rd), Microsoft Security Suite (9th), Secure Email Gateway (SEG) (2nd)
 

Mindshare comparison

As of August 2026, in the Email Security category, the mindshare of Cloudflare One is 1.7%, up from 1.4% compared to the previous year. The mindshare of Heimdal Email Security is 0.5%, up from 0.2% compared to the previous year. The mindshare of Microsoft Defender for Office 365 is 5.7%, down from 11.6% 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%
Cloudflare One1.7%
Heimdal Email Security0.5%
Other92.1%
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

"We mostly use Cloudflare WAF, and gets basic Cloudflaire DDoS, caching as extra bonus . We like the factor these features are all integrated into 1 console, simple to manage."
"The best feature is rate limiting. If I'm expecting 500 visits per hour, Cloudflare will limit the requests if I suddenly get 50,000."
"Clover is the best product globally."
"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."
"Cloudflare is by far the most effective solution that I have come across."
"The solution has different options that can be used to differentiate DDoS attacks."
"Cloudflare is simple to use."
"I'm very satisfied with the environment and the dashboard."
"It is stable and reliable."
"Safe attachments, safe links, policies, and the ability to protect from zero-day threats are the most valuable features."
"The most valuable feature of Microsoft Defender for Office 365 is the ease of use."
"Microsoft Defender for Office 365 helps people to work remotely. It is a secure solution. We don't need to use our company's computers or get VPN connections to the networks. I can control how they share screens and what they send to the devices. It keeps our organizations confidential and sensitive information safe."
"Some of the valuable features on the email side are anti-phishing, anti-malware, and Safe Links."
"Does a thorough job of examining email and URLs for malicious content."
"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."
"Microsoft so far has been good; we haven't faced any kind of disruption or anything else, it's a good product and good platform, I must say, and overall it's a good product and good service and we haven't dealt with bugs or glitches."
"Microsoft Defender has a feature to protect each and every attachment. Even if it's an encrypted attachment, it will check for any potential threats."
 

Cons

"Our customers no longer use Cloudflare because its service is subpar."
"Cloudflare Zero Trust Platform needs to improve its documentation. It took time to do the implementation."
"Feedback could be enhanced."
"When there are any dynamic changes in complex applications, the tool takes a lot of time, making its analytics-related area a major matter of concern where improvements are needed."
"The pricing is an area that can be improved. Pricing, as far as I recall, was the source of our problems."
"The onboarding process can be improved a little bit."
"For the topic of improvement, providing some training material is one of my suggestions."
"Cloudflare DDoS has poor technical support."
"The solution could be less expensive."
"Microsoft could improve by offering recommendations for domain spoofing attacks, especially scenarios where DNS records like SPF, DKIM, and DMARC are not properly published."
"The inbuilt analysis of false positives can be faster. It's not slow, but it can be faster."
"Microsoft should provide more documentation for users so they can self-educate. I would like to see more documentation for advanced security features."
"Sometimes I have to recategorize things when it takes the wrong step and I do not want it to classify something as suspicious."
"The phishing and spam filters could use some improvement."
"It would be better if it were more scalable. It depends on the architecture, but we would like to make it more scalable for both data centers."
"One area for improvement is support, in terms of being able to reach them and, especially, technical support for configuration."
"The UI needs to be more user-friendly."
 

Pricing and Cost Advice

"The prices are slightly expensive."
"Cloudflare Zero Trust Platform's pricing is good."
"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."
"The solution is not that 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's pricing lacks transparency."
Information not available
"I was working in the government and it was too expensive for us to use our Microsoft products."
"Microsoft Defender for Office 365 comes with Microsoft Windows. It is free with the operating system."
"The product is very expensive."
"It is much more expensive than using another solution because we have had to include some options and upgrade our license."
"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."
"Microsoft Defender for Office 365 is an add-on to the Office license. Many customers are purchasing this solution."
"The pricing is normal. Considering its popularity, it's not overpriced."
"Compared to other brands, Microsoft Defender for Office 365's pricing is competitive."
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Top Industries

By visitors reading reviews
Construction Company
19%
Comms Service Provider
11%
Outsourcing Company
9%
Financial Services Firm
8%
Construction Company
21%
Manufacturing Company
9%
Performing Arts
7%
Comms Service Provider
7%
Computer Software Company
11%
Manufacturing Company
9%
Financial Services Firm
9%
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 Enterprise11
Large Enterprise32
 

Questions from the Community

What needs improvement with Cloudflare Zero Trust Platform?
In my opinion, Cloudflare One can be improved mainly through compatibility, as the integration should be much simpler...
What is your primary use case for Cloudflare Zero Trust Platform?
Cloudflare One's primary use case for my organization is to protect servers and to provide remote access with the VPN...
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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: July 2026.
908,800 professionals have used our research since 2012.