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AppRiver Email Security vs Microsoft Defender for Office 365 comparison

 

Comparison Buyer's Guide

Executive SummaryUpdated on Dec 3, 2024

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

AppRiver Email Security
Ranking in Email Security
38th
Average Rating
9.0
Reviews Sentiment
6.6
Number of Reviews
2
Ranking in other categories
No ranking in other categories
Microsoft Defender for Offi...
Ranking in Email Security
1st
Average Rating
8.4
Reviews Sentiment
6.9
Number of Reviews
53
Ranking in other categories
Email Archiving (1st), Advanced Threat Protection (ATP) (2nd), Microsoft Security Suite (10th), Secure Email Gateway (SEG) (1st)
 

Mindshare comparison

As of October 2025, in the Email Security category, the mindshare of AppRiver Email Security is 0.9%, down from 1.2% compared to the previous year. The mindshare of Microsoft Defender for Office 365 is 11.4%, down from 14.8% compared to the previous year. It is calculated based on PeerSpot user engagement data.
Email Security Market Share Distribution
ProductMarket Share (%)
Microsoft Defender for Office 36511.4%
AppRiver Email Security0.9%
Other87.7%
Email Security
 

Featured Reviews

John Zupancic - PeerSpot reviewer
Pricing that is competitive, excellent technical support, and email security
They do a better job of distinguishing between what's real and what's not than most of the other solutions we've tried. They are very easy to use. We don't have as many problems with email security. They have some areas that could be improved. For example, we also use Zix email Encryption for email encryption, which was clunky and could be improved, but the email security itself has been excellent.
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.

Quotes from Members

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

Pros

"It's easy to use and user-friendly. Users can also easily release spam emails."
"They are very easy to use."
"The product is not resource-intensive."
"Microsoft Defender for Office 365's most valuable feature is its performance."
"Defender for Office 365 has helped eliminate having to look at multiple dashboards and that is the aspect I like most about it. It is simpler, effective, and convenient. The users like the process efficiency."
"The initial setup was easy."
"Does a thorough job of examining email and URLs for malicious content."
"It also gives the vulnerability status according to the versions you have selected. Let's say you have Google Chrome. It mentions the versions it has, and it updates. Within two hours of an update, it is reflected in the dashboard. That's really nice to have."
"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."
"The ability to respond to threats if very important."
 

Cons

"Email security checks contain a small number of false positives."
"It needs to make sure that the application is up to date with new attacks. They should also send us the demo or introductions for their new incoming features."
"The visibility for the weaknesses in the system and unauthorized access can be improved."
"Microsoft security solutions work as expected. They are constantly updating the solutions to make them better. At the same time, the changes can impact a customer's environment, and we need to adjust settings. Sometimes we aren't aware of the changes, and nothing is pushed from the backend automatically."
"Specifically, within Microsoft Defender for Office 365, I want it to improve the DLP capabilities."
"Configuration at the mid-level could be improved for the support team."
"We need to be able to whitelist data at the backend."
"In some situations, it has not been able to pick impersonated emails having no attachments. Technical support definitely has a scope for improvement."
"Microsoft sometimes has downtime, and we'll get several incidents coming in back to back. We have a huge backlog of notifications, many of which may be false positives. However, there might be serious alerts, so we can't risk dismissing all of them at once."
"The phishing and spam filters could use some improvement."
 

Pricing and Cost Advice

"They're fairly inexpensive, but they're right in the ballpark of most of the other online products like that."
"I can rate it five out of ten because there are different platforms that also offer the same services for lower prices. But AppRiver is more flexible."
"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."
"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."
"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."
"Microsoft Defender is expensive. I typically recommend it only if clients have the budget. Otherwise, I would suggest an alternative."
"From the pricing point of view, like any other product in the market, there is scope for negotiation."
"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."
"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."
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Top Industries

By visitors reading reviews
Computer Software Company
11%
Manufacturing Company
10%
Comms Service Provider
8%
Retailer
7%
Computer Software Company
15%
Financial Services Firm
8%
Manufacturing Company
8%
Comms Service Provider
6%
 

Company Size

By reviewers
Large Enterprise
Midsize Enterprise
Small Business
No data available
By reviewers
Company SizeCount
Small Business23
Midsize Enterprise8
Large Enterprise27
 

Questions from the Community

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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?
I think that Microsoft Defender for Office 365 could be improved if it could use VirusTotal to compare the programs or anything that I download. VirusTotal helps to identify viruses, malware, troja...
 

Also Known As

AppRiver Advanced Email Security
MS Defender for Office 365
 

Overview

 

Sample Customers

IHMC
Microsoft Defender for Office 365 is trusted by companies such as Ithaca College.
Find out what your peers are saying about AppRiver Email Security vs. Microsoft Defender for Office 365 and other solutions. Updated: September 2025.
868,787 professionals have used our research since 2012.