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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
7.0
Number of Reviews
52
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 July 2025, in the Secure Email Gateway (SEG) category, the mindshare of Microsoft Defender for Office 365 is 28.5%, down from 37.5% compared to the previous year. The mindshare of Retarus Email Security is 0.3%, up from 0.2% compared to the previous year. It is calculated based on PeerSpot user engagement data.
Secure Email Gateway (SEG)
 

Featured Reviews

Tolu Omolaja - PeerSpot reviewer
Great URL scanning and attachment scanning, but I would like more proactive threat analysis
The two main features that prove most beneficial for us are URL scanning and attachment scanning. URL scanning involves an automatic scan of links and emails. When a user clicks on a link within an email, the system promptly checks the link's safety. If the link is deemed safe, access is granted automatically. However, if it is flagged as unsafe, we receive feedback and notification to caution us about the potentially harmful link. At this point, we are presented with the option to proceed or return. I have personally witnessed the system identify a few unsafe links, making this the primary advantage of using the solution. The second crucial aspect is the scanning of attachments. When an email containing an attachment arrives, we receive a notification of the new email, along with information that the attachment is being scanned for threats. This additional layer of security provides peace of mind for our organization. While Microsoft Defender for Office 365 offers numerous features, these two stand out as particularly impressive and valuable to us.
WAKKAS AHMAD - PeerSpot reviewer
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

"Defender helps us prioritize threats across our organization."
"The ability to respond to threats if very important."
"The most valuable feature of Microsoft Defender for Office 365 is its spam filter."
"The two main features that prove most beneficial for us are URL scanning and attachment scanning."
"The most valuable feature of Microsoft Defender for Office 365 is the ease of use."
"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."
"The initial setup is straightforward. You just add the license, click it, and then you can set up the rules. It is quite simple."
"It also gives me good visibility because, with Defender, I'm using a Microsoft product to defend Microsoft products. The integration was really seamless and I have wide visibility because it picks up almost everything. Literally, I can see almost every activity that happens, from the e-mail to the workstation itself."
"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

"I'd like some additional features any product can give me to protect our environment in a better way."
"You should be able to deploy Defender for every subscription without the need to add servers."
"The visibility into threats is not up to the mark, as I do not have control. I rate my experience with Microsoft Defender for Office 365 as six out of ten due to troubleshooting and pricing concerns."
"This product's effectiveness could be improved, in terms of detecting unwanted spam or even malware between the emails, compared to other products."
"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."
"Microsoft needs to broaden its global support presence by establishing teams of subject-matter experts in all regions."
"The XDR dashboard has room for improvement."
"The UI needs to be more user-friendly."
"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

"It's a user-base subscription."
"The pricing is normal. Considering its popularity, it's not overpriced."
"From the pricing point of view, like any other product in the market, there is scope for negotiation."
"I know that the product is incredibly expensive."
"The pricing has become expensive."
"The product is very expensive."
"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."
"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
Computer Software Company
16%
Financial Services Firm
8%
Manufacturing Company
8%
Government
6%
No data available
 

Company Size

By reviewers
Large Enterprise
Midsize Enterprise
Small Business
No data available
 

Questions from the Community

What do you like most about Microsoft Defender for Office 365?
Threat Explorer is an invaluable tool for me, and it plays a crucial role in helping me discern the origins of various email campaigns, pinpointing where they emanate from, and identifying the indi...
What is your experience regarding pricing and costs for Microsoft Defender for Office 365?
Microsoft is quite affordable with a lot of features available for any size organization.
What needs improvement with Microsoft Defender for Office 365?
Microsoft could improve by offering recommendations for domain spoofing attacks, especially scenarios where DNS records like SPF, DKIM, and DMARC are not properly published. It's essential to enhan...
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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, Abnormal Security, Proofpoint and others in Secure Email Gateway (SEG). Updated: July 2025.
863,679 professionals have used our research since 2012.