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Heimdal Email Security vs Microsoft Defender for Office 365 comparison

 

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

Heimdal Email Security
Ranking in Email Security
66th
Average Rating
9.0
Reviews Sentiment
7.9
Number of Reviews
1
Ranking in other categories
Fraud Detection and Prevention (61st)
Microsoft Defender for Offi...
Ranking in Email Security
1st
Average Rating
8.4
Reviews Sentiment
6.8
Number of Reviews
60
Ranking in other categories
Email Archiving (1st), Advanced Threat Protection (ATP) (2nd), Microsoft Security Suite (10th), Secure Email Gateway (SEG) (1st)
 

Mindshare comparison

As of February 2026, in the Email Security category, the mindshare of Heimdal Email Security is 0.3%, up from 0.2% compared to the previous year. The mindshare of Microsoft Defender for Office 365 is 9.1%, down from 13.7% compared to the previous year. It is calculated based on PeerSpot user engagement data.
Email Security Market Share Distribution
ProductMarket Share (%)
Microsoft Defender for Office 3659.1%
Heimdal Email Security0.3%
Other90.6%
Email Security
 

Featured Reviews

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

"It is stable and reliable."
"The initial setup is straightforward. You just add the license, click it, and then you can set up the rules. It is quite simple."
"The ability to respond to threats if very important."
"The solution is very easy to use. All you have to do is to assign the license to the end-user and it's done. The customer will only have the feature activated, and the solution will monitor the emails to determine if they are a threat or not."
"The insights provided with Microsoft Defender for Office 365 are helpful because it comes with the E5 license, and by default, we can use a lot of capabilities."
"Since we have started using the solution, there have been fewer compromises."
"Safe attachments, safe links, policies, and the ability to protect from zero-day threats are the most valuable features."
"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."
"The technical support is good and quick to resolve issues."
 

Cons

"The solution could be less expensive."
"The pre-sales cost calculations could be more transparent."
"Microsoft Defender for Office 365 must improve the overall management style, including the GUI. It also needs to change the filters so that it is easy to whitelist and blacklist data."
"Specifically, within Microsoft Defender for Office 365, I want it to improve the DLP capabilities."
"The only thing they should improve is the licensing model. They should stop changing it. A year ago, the five features I mentioned were included in one product. Now, three of them are bundled into one product, and you have to pay extra for the other two. I don't mind paying extra, but I don't want them to change it every year or every six months. I need to know what I'm looking at and not worry about it next year."
"We need a separate license and we don't know how to get the license that is required."
"I'd like some additional features any product can give me to protect our environment in a better way."
"Microsoft needs to broaden its global support presence by establishing teams of subject-matter experts in all regions."
"One area for improvement is integration. For example, when it comes to external SaaS platforms, we were not able to get a lot of information on integrations with such apps for security and authentication."
 

Pricing and Cost Advice

Information not available
"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."
"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."
"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."
"It is much more expensive than using another solution because we have had to include some options and upgrade our license."
"The product is expensive."
"For large enterprise organizations, they can definitely afford it, but for small and medium organizations, they might struggle to cover the expenses."
"Microsoft Defender for Office 365 comes with Microsoft Windows. It is free with the operating system."
"The pricing is normal. Considering its popularity, it's not overpriced."
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Top Industries

By visitors reading reviews
No data available
Computer Software Company
13%
Financial Services Firm
8%
Manufacturing Company
8%
Comms Service Provider
6%
 

Company Size

By reviewers
Large Enterprise
Midsize Enterprise
Small Business
No data available
By reviewers
Company SizeCount
Small Business23
Midsize Enterprise10
Large Enterprise31
 

Questions from the Community

Ask a question
Earn 20 points
What needs improvement with Microsoft Defender for Office 365?
The inbuilt analysis of false positives can be faster. It's not slow, but it can be faster.
What is your primary use case for Microsoft Defender for Office 365?
My use case for Microsoft Defender for Office 365 is for email protection, safe links, protection of links, documents, protecting my documents, and protecting attachments. I also use it to conduct ...
 

Also Known As

MailSentry
MS Defender for Office 365
 

Overview

 

Sample Customers

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 Microsoft, Proofpoint, Check Point Software Technologies and others in Email Security. Updated: January 2026.
881,733 professionals have used our research since 2012.