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Microsoft Defender for Office 365 vs Mimecast Mailbox Continuity comparison

 

Comparison Buyer's Guide

Executive SummaryUpdated on Jun 29, 2025

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 Email Archiving
1st
Average Rating
8.4
Reviews Sentiment
6.8
Number of Reviews
60
Ranking in other categories
Email Security (1st), Advanced Threat Protection (ATP) (2nd), Microsoft Security Suite (10th), Secure Email Gateway (SEG) (1st)
Mimecast Mailbox Continuity
Ranking in Email Archiving
7th
Average Rating
8.0
Reviews Sentiment
6.1
Number of Reviews
6
Ranking in other categories
No ranking in other categories
 

Mindshare comparison

As of January 2026, in the Email Archiving category, the mindshare of Microsoft Defender for Office 365 is 18.2%, down from 23.1% compared to the previous year. The mindshare of Mimecast Mailbox Continuity is 5.6%, up from 4.7% compared to the previous year. It is calculated based on PeerSpot user engagement data.
Email Archiving Market Share Distribution
ProductMarket Share (%)
Microsoft Defender for Office 36518.2%
Mimecast Mailbox Continuity5.6%
Other76.2%
Email Archiving
 

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.
Todd Blake - PeerSpot reviewer
Senior IT Specialist at COMMUNITY HEALTH CONNECTIONS INC
Provides peace of mind and expands well but needs a better interface
It's a hosted solution. I'm not sure which version of the solution Im on at this time. I would advise others to research all the options out there and see what the best fit is. We started this mailbox continuity project before we moved to Office 365. And now that we've moved to Office 365, we kind of don't need this piece of technology in the same way that we used to need it when we had an on-prem exchange. Therefore, make sure that you actually need it and then research to find the best options. Overall, I would rate the solution seven out of ten.

Quotes from Members

We asked business professionals to review the solutions they use. Here are some excerpts of what they said:
 

Pros

"The DLP feature of Microsoft Defender for Office 365 is valuable, and we also use the DLP feature for email real-time detection."
"I like its investigation capabilities, as that is what is most important to me. It is fairly simple with a user-friendly interface."
"The ability to respond to threats if very important."
"The coolest feature of Microsoft Defender for Office 365 is its ability to look for phishing emails."
"The benefit that stands out to me is the ability for multiple individuals to collaborate simultaneously within the same document. Additionally, there is the option to save the document directly in the integrated OneDrive or SharePoint."
"I would say that 90% of the spam and phishing attack emails get blocked right off the bat."
"The initial setup is straightforward. You just add the license, click it, and then you can set up the rules. It is quite simple."
"The good part is that you don't have to configure it, which is very convenient."
"The most valuable feature of Mimecast Mailbox Continuity is real-time alerts."
"The security is pretty good, and that's why we're going to upgrade to an even more advanced package. We used it when we had a power issue, and it works. It has been pretty reliable, and the support has been quite good."
"It has all the features required for distribution, such as the ability to mail."
"The Large File Send feature comes in handy when you have to send fairly large attachments."
"Mimecast has some good support services in place."
"We're now certain business-critical mail is perfectly protected in multiple ways."
 

Cons

"The GUI is sometimes slow to fetch the device report and could be improved."
"The pre-sales cost calculations could be more transparent."
"We need to be able to whitelist data at the backend."
"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."
"I'd like some additional features any product can give me to protect our environment in a better way."
"Configuration requires going to a lot of places rather than just accessing one tab."
"Microsoft Defender for Office 365 could improve by giving customers information on techniques to prevent threats. For example, information about best practices on how to protect their own devices against hackers and scammers, such as educational information or training. This would help others have a better understanding of cyber security. Additionally, there can be more security features added."
"Several simulation options are available within 365, and the phishing simulation could be better."
"The price of the solution is expensive. It can improve by reducing the price."
"The interface isn't the best. How everything works on the back end is confusing."
"The solution is expensive in comparison to similar solutions."
"The interface and the documentation could be improved. They can also include some more training resources and content like video. While setting things up, I had to search for the information quite a bit. It took me time to find the correct way to do something. The information is there, but it is sort of all over the place. They can create a better help knowledge base or help portal. It retains your email for 45 days. They can maybe increase this duration."
"Technical support has been slower than it was in the past, likely due to the pandemic."
 

Pricing and Cost Advice

"For large enterprise organizations, they can definitely afford it, but for small and medium organizations, they might struggle to cover the expenses."
"The license is expensive because the cost is based on the number of users."
"The pricing is normal. Considering its popularity, it's not overpriced."
"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."
"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 know that the product is incredibly expensive."
"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."
"Defender is a little bit more expensive as compared to others. We are in the manufacturing environment. So, we don't have a high budget for all of our endpoint devices. Its cost is a major concern for us."
"Its price is in the middle range. It is a structured licensing model where there are various components that you can add or choose to add or not."
"The price of Mimecast Mailbox Continuity is expensive."
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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.
DAC Beachcroft, OceanFirst, Currie & Brown, Alexander Forbes, Lagan Group, Lals Group, Greater Manchester Fire and Rescue Service, Wedlake Bell, Macmillan Cancer Support, Bech-Bruun
Find out what your peers are saying about Microsoft Defender for Office 365 vs. Mimecast Mailbox Continuity and other solutions. Updated: December 2025.
881,082 professionals have used our research since 2012.