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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
7.1
Number of Reviews
52
Ranking in other categories
Email Archiving (1st), Email Security (1st), Advanced Threat Protection (ATP) (1st), Microsoft Security Suite (11th)
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 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

"One of the best features of the tool is its capability to aggregate insights from different workloads, basically from the Office 365 and endpoints part."
"The stability of Microsoft Defender for Office 365 is fantastic."
"The technical support is good and quick to resolve issues."
"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 initial setup was easy."
"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."
"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."
"Microsoft Defender for Office 365's most valuable feature is its performance."
"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."
"The changes to customer service, specifically the new model for support agreements, are not favorable."
"There is a different console for different things; I just want one consolidated console."
"The custom alerts have to improve a lot."
"We need to be able to whitelist data at the backend."
"The certification training for Defender for 365 needs to be deeper and incorporate Sentinel. I took all the security courses except one, and Sentinel isn't included."
"The visibility for the weaknesses in the system and unauthorized access can be improved."
"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."
"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 is expensive. I typically recommend it only if clients have the budget. Otherwise, I would suggest an alternative."
"For large enterprise organizations, they can definitely afford it, but for small and medium organizations, they might struggle to cover the expenses."
"It is much more expensive than using another solution because we have had to include some options and upgrade our license."
"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."
"The license is expensive because the cost is based on the number of users."
"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."
"Microsoft Defender for Office 365 is an add-on to the Office license. Many customers are purchasing this solution."
"The pricing has become expensive."
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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?
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, Proofpoint, Abnormal Security and others in Secure Email Gateway (SEG). Updated: May 2025.
851,471 professionals have used our research since 2012.