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Microsoft Defender for Office 365 vs Retarus Email Security 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

Microsoft Defender for Offi...
Ranking in Secure Email Gateway (SEG)
1st
Average Rating
8.4
Reviews Sentiment
6.8
Number of Reviews
60
Ranking in other categories
Email Archiving (1st), Email Security (1st), Advanced Threat Protection (ATP) (2nd), Microsoft Security Suite (10th)
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 January 2026, in the Secure Email Gateway (SEG) category, the mindshare of Microsoft Defender for Office 365 is 24.2%, down from 31.1% compared to the previous year. The mindshare of Retarus Email Security is 0.8%, up from 0.2% compared to the previous year. It is calculated based on PeerSpot user engagement data.
Secure Email Gateway (SEG) Market Share Distribution
ProductMarket Share (%)
Microsoft Defender for Office 36524.2%
Retarus Email Security0.8%
Other75.0%
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 feature I like the most about Microsoft Defender for Office 365 is that it typically runs in the background—you do not know it is there until you need to access it."
"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."
"Does a thorough job of examining email and URLs for malicious content."
"The good part is that you don't have to configure it, which is very convenient."
"The product's scalability is good."
"It has significantly decreased my time to detection and response."
"The most valuable aspect of Microsoft Defender for Office 365 is its ability to protect us from malware."
"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

"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."
"To improve Microsoft Defender for Office 365, it would be nice to have more accessibility for users to see on their end what they are doing that could cause a threat."
"Microsoft security solutions work as expected. They are constantly updating the solutions to make them better. At the same time, the changes can impact a customer's environment, and we need to adjust settings. Sometimes we aren't aware of the changes, and nothing is pushed from the backend automatically."
"Microsoft needs to broaden its global support presence by establishing teams of subject-matter experts in all regions."
"Microsoft Defender for Office 365 is not up to the mark in comparison with Wiz or Palo Alto."
"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 think that Microsoft Defender for Office 365 could be improved if it could use VirusTotal to compare the programs or anything that I download."
"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 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."
"Compared to other brands, Microsoft Defender for Office 365's pricing is competitive."
"While Microsoft Defender for Office 365 necessitates pricier E3 or E5 subscriptions, the extensive functionality offered by these licenses across various Microsoft products justifies the investment."
"I was working in the government and it was too expensive for us to use our Microsoft products."
"The pricing has become expensive."
"Microsoft Defender is expensive. I typically recommend it only if clients have the budget. Otherwise, I would suggest an alternative."
"Microsoft Defender for Office 365 comes with Microsoft Windows. It is free with the operating system."
"It's a user-base subscription."
Information not available
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Top Industries

By visitors reading reviews
Computer Software Company
14%
Financial Services Firm
8%
Manufacturing Company
8%
Comms Service Provider
6%
No data available
 

Company Size

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

Questions from the Community

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 ...
Ask a question
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Also Known As

MS Defender for Office 365
No data available
 

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 Microsoft, Proofpoint, Abnormal AI and others in Secure Email Gateway (SEG). Updated: January 2026.
881,082 professionals have used our research since 2012.