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Microsoft Defender for Office 365 vs N-able Mail Assure comparison

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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 Email Archiving
1st
Ranking in Email Security
2nd
Average Rating
8.4
Reviews Sentiment
6.8
Number of Reviews
61
Ranking in other categories
Advanced Threat Protection (ATP) (3rd), Microsoft Security Suite (9th), Secure Email Gateway (SEG) (2nd)
N-able Mail Assure
Ranking in Email Archiving
14th
Ranking in Email Security
42nd
Average Rating
1.0
Reviews Sentiment
4.3
Number of Reviews
1
Ranking in other categories
No ranking in other categories
 

Mindshare comparison

As of September 2026, in the Email Security category, the mindshare of Microsoft Defender for Office 365 is 5.2%, down from 11.1% compared to the previous year. The mindshare of N-able Mail Assure is 0.8%, up from 0.4% compared to the previous year. It is calculated based on PeerSpot user engagement data.
Email Security Mindshare Distribution
ProductMindshare (%)
Microsoft Defender for Office 3655.2%
N-able Mail Assure0.8%
Other94.0%
Email Security
 

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.
This is a dud product with inferior spam filtering
This is a dud product with inferior spam filtering versus alternatives like SpamHero, and the continuity feature is essentially marketing fluff. Failed deliveries, for example, they don't count it as an issue so those messages won't be queued for another delivery attempt. As I understand it from talking to their support, if the server pings or sends any response at all, then Mail Assure will not keep a copy. It will also weirdly mark messages during that outage as rejected, so it's not like Mail Assure doesn't know that the message never reached the user(s).

Quotes from Members

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

Pros

"It definitely is a must for email protection and O365 app DLP, and combined with Microsoft Defender for Endpoint, Microsoft Defender for Identity, and MCAS, it provides a holistic solution for threat protection, email protection, O365 apps protection, and DLP for both internal and external risks."
"It has helped us in improving our security posture; it detects any kind of attack or abnormal behavior in accessing the system and sends an alert to the administrator who can check, understand, and review on time to ensure that all activities are legit."
"Since we have started using the solution, there have been fewer compromises."
"Overall, I would rate Microsoft Defender for Office 365 at a ten."
"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."
"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 most valuable feature is the integration; it's a single console, so we don't have to switch around between multiple products, and another valuable feature is the ease of operations and maintenance."
"The only benefit from Mail Assure is its white label feature and its per-user licensing plus the ability to package archiving and spam protection into a single interface."
 

Cons

"Microsoft Defender for Office 365 should be more proactive."
"This product's effectiveness could be improved, in terms of detecting unwanted spam or even malware between the emails, compared to other products."
"We need a separate license and we don't know how to get the license that is required."
"The UI needs to be more user-friendly."
"In one of the reports I can get the exact place where a vulnerable file resides. But for that, I need to explicitly go into the device and check. If they could include that file part in the report, without my having to go to the device itself, that would help."
"I am generally satisfied with how it currently is. If I could improve anything, I would reduce the cost."
"There's room for improvement regarding the time frame for retrieving emails."
"In some situations, it has not been able to pick impersonated emails having no attachments. Technical support definitely has a scope for improvement."
"This is a dud product with inferior spam filtering versus alternatives like SpamHero, and the continuity feature is essentially marketing fluff."
 

Pricing and Cost Advice

"The license is expensive because the cost is based on the number of users."
"The product is very expensive."
"I was working in the government and it was too expensive for us to use our Microsoft products."
"It's a user-base subscription."
"For large enterprise organizations, they can definitely afford it, but for small and medium organizations, they might struggle to cover the expenses."
"I know that the product is incredibly expensive."
"Microsoft Defender for Office 365 is an add-on to the Office license. Many customers are purchasing this solution."
"Microsoft Defender for Office 365 comes with Microsoft Windows. It is free with the operating system."
Information not available
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Top Industries

By visitors reading reviews
Computer Software Company
11%
Manufacturing Company
10%
Financial Services Firm
9%
Comms Service Provider
8%
Construction Company
15%
Computer Software Company
11%
Comms Service Provider
9%
Government
7%
 

Company Size

By reviewers
Large Enterprise
Midsize Enterprise
Small Business
By reviewers
Company SizeCount
Small Business24
Midsize Enterprise11
Large Enterprise32
No data available
 

Questions from the Community

What is your experience regarding pricing and costs for Microsoft Defender for Office 365?
My experience with pricing, setup, and licensing is that it's actually quite reasonable even on the licensing side as a standalone product. It's very competitive compared to what competitors are ch...
What needs improvement with Microsoft Defender for Office 365?
I think Microsoft Defender for Office 365 can be improved by creating more educational pieces about not just looking for malware. We are seeing a lot more malware-less emails that Defender for Offi...
What is your primary use case for Microsoft Defender for Office 365?
My main use cases for Microsoft Defender for Office 365 include email hygiene.
Ask a question
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Also Known As

MS Defender for Office 365
SolarWinds MSP Mail, SolarWinds Mail Assure, SolarWinds MSP Mail Assure
 

Overview

 

Sample Customers

Microsoft Defender for Office 365 is trusted by companies such as Ithaca College.
eNet Systems, WinAdmins, Newport Systems
Find out what your peers are saying about Proofpoint, Microsoft, Check Point Software Technologies and others in Email Security. Updated: August 2026.
914,109 professionals have used our research since 2012.