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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...
Average Rating
8.4
Reviews Sentiment
7.1
Number of Reviews
49
Ranking in other categories
Email Security (1st), Advanced Threat Protection (ATP) (1st), Microsoft Security Suite (11th)
Retarus Email Security
Average Rating
8.0
Reviews Sentiment
5.6
Number of Reviews
1
Ranking in other categories
Secure Email Gateway (SEG) (15th)
 

Mindshare comparison

As of May 2025, in the Secure Email Gateway (SEG) category, the mindshare of Microsoft Defender for Office 365 is 29.5%, down from 39.3% compared to the previous year. The mindshare of Retarus Email Security is 0.2%, 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

"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."
"The product's scalability is good."
"Microsoft Defender for Office 365's most valuable features are safe attachments and safe links."
"Some of the valuable features on the email side are anti-phishing, anti-malware, and Safe Links."
"It gives us visibility into threats and, for endpoints, it helps us to prioritize threats. We used to have a lack of visibility, but now our time to detect and respond has decreased."
"The most valuable feature is protection against malicious links, fishing, and impersonation. You can train people to be aware of these threats, but they're not always careful. When they're using their phones between meetings, they click on a link, and it's game over."
"Defender for 365 is a comprehensive cloud-based solution. The value of the cloud is that you aren't alone. Threat intelligence and analytics are shared in the cloud. We don't have to find the solution alone. If you face an unknown threat with traditional solutions like Trend Micro and Symantec, you need to open a case and send your information to them to analyze forensically and identify the source of the attack."
"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

"We are always looking for others tools to increase automation on tasks. There can be better integration with other solutions, such as PowerPoint and email."
"This product's effectiveness could be improved, in terms of detecting unwanted spam or even malware between the emails, compared to other products."
"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 could improve by offering recommendations for domain spoofing attacks, especially scenarios where DNS records like SPF, DKIM, and DMARC are not properly published."
"The GUI is sometimes slow to fetch the device report and could be improved."
"Too many false positives and lacks an accurate capability to detect malicious SharePoint sites."
"I am generally satisfied with how it currently is. If I could improve anything, I would reduce the cost."
"Configuring the default strategies and policies in Microsoft Defender for Cloud Apps generates a lot of noise and false positives."
"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

"Microsoft Defender for Office 365 is an add-on to the Office license. Many customers are purchasing this solution."
"Compared to other brands, Microsoft Defender for Office 365's pricing is competitive."
"The product is very expensive."
"It's a user-base subscription."
"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."
"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 for Office 365 comes with Microsoft Windows. It is free with the operating system."
"From the pricing point of view, like any other product in the market, there is scope for negotiation."
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Top Industries

By visitors reading reviews
Computer Software Company
16%
Financial Services Firm
9%
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?
Money-wise, it is a part of the Office 365 ( /products/office-365-reviews ) suite, making it slightly more expensive compared to Trend Micro. Although Defender is free, you have to pay separately f...
What needs improvement with Microsoft Defender for Office 365?
The main area for improvement is simplifying the implementation and rollout process. There are many conditions to be met, making it challenging to ensure every system is protected. Troubleshooting ...
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Also Known As

MS Defender for Office 365
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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 Security and others in Secure Email Gateway (SEG). Updated: March 2025.
849,686 professionals have used our research since 2012.