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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 January 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 9.6%, down from 13.9% 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 3659.6%
Heimdal Email Security0.3%
Other90.1%
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 product's scalability is good."
"It’s easy to handle integrations, and we don't need a lot of people in our IT team."
"Does a thorough job of examining email and URLs for malicious content."
"Safe attachments, safe links, policies, and the ability to protect from zero-day threats are the most valuable features."
"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."
"Microsoft Defender for Office 365 facilitates efficient management and updates through the cloud. We do not have to worry about incompatibilities. It just works."
"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."
"The most valuable feature is the integration. It's a single console, so we don't have to switch around between multiple products. Another valuable feature is the ease of operations and maintenance."
 

Cons

"The solution could be less expensive."
"This product's effectiveness could be improved, in terms of detecting unwanted spam or even malware between the emails, compared to other products."
"The inbuilt analysis of false positives can be faster. It's not slow, but it can be faster."
"The UI needs to be more user-friendly."
"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 needs to be an improvement in integrating the product to work across multiple operating systems, and to have better support for non-Microsoft file types."
"Microsoft should provide more documentation for users so they can self-educate. I would like to see more documentation for advanced security features."
"There's room for improvement regarding the time frame for retrieving emails."
"The cost of Security Copilot is up there right now, and I think it needs to come down for more people to adopt."
 

Pricing and Cost Advice

Information not available
"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."
"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."
"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."
"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."
"It's a user-base subscription."
"I know that the product is incredibly expensive."
"Microsoft Defender is expensive. I typically recommend it only if clients have the budget. Otherwise, I would suggest an alternative."
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Top Industries

By visitors reading reviews
No data available
Computer Software Company
14%
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

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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.
881,082 professionals have used our research since 2012.