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Fortinet FortiMail vs Microsoft Defender for Office 365 comparison

 

Comparison Buyer's Guide

Executive SummaryUpdated on Apr 20, 2025

Review summaries and opinions

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

ROI

Sentiment score
7.6
Fortinet FortiMail boosts email security, saves costs, reduces spam, and consolidates functions, increasing reliability and efficiency for users.
Sentiment score
7.2
Microsoft Defender for Office 365 enhances email protection, reduces costs, and increases productivity, offering invaluable data security.
It offers cost savings compared to Cisco, which was very expensive.
It has also decreased our time to detection and response by about 15 to 20 percent.
Overall, cost of owning and operating our system goes down.
It's hard to quantify the return on investment we've seen from Microsoft Defender for Office 365.
 

Customer Service

Sentiment score
6.5
Fortinet FortiMail is praised for competent support, though some experience delays; elite support offers quicker assistance for a fee.
Sentiment score
7.0
Microsoft Defender for Office 365 offers reliable support, praised for responsiveness, despite some challenges with clarity and third-party resolutions.
I have direct communication with Kenyan system engineers and local support in Ethiopia, enabling good support.
Fortinet's technical support offers high-quality support.
Over the past two years, there have been no critical problems.
we opened tickets, and they typically resolve them quickly.
Customer service and support have been fantastic.
 

Scalability Issues

Sentiment score
7.4
Fortinet FortiMail is scalable, integrates well with infrastructures, effectively handles email volumes, and is favored by various industries.
Sentiment score
8.2
Microsoft Defender for Office 365 scales seamlessly across configurations, supporting thousands of users with effortless integration and optimal performance.
We have never faced scalability problems, and Microsoft manages it effectively.
Microsoft Defender for Office 365 scales transparently for us, as we grew from 1,000 users to 3,000 users, and we didn't notice much difference.
 

Stability Issues

Sentiment score
8.4
Fortinet FortiMail is praised for its high stability, minimal downtime, and user satisfaction in both on-premises and cloud deployments.
Sentiment score
7.7
Microsoft Defender for Office 365 is highly reliable, offering stable performance, quick issue resolution, and high user satisfaction ratings.
This stability is consistent across Fortinet products, including FortiGate firewall.
The solution is stable, as we have been using it for the past two years.
I would assess the stability and reliability of Microsoft Defender for Office 365 as very stable, with barely any issues.
Overall, the stability and reliability of Microsoft Defender for Office 365 are good.
 

Room For Improvement

Fortinet FortiMail needs upgrades in interface, integration, user management, security features, and overall user-friendliness for improved functionality.
Microsoft Defender for Office 365 needs enhanced virus protection, compatibility, UI, integration, reporting, and cost transparency to improve user experience.
Providing comprehensive documentation on how to deploy and configure would improve the solution.
The transition from on-premises devices to virtual appliances may be necessary as more organizations migrate email services to the cloud.
The area that could use some improvement in Fortinet FortiMail is the integration process.
The main area for improvement is simplifying the implementation and rollout process.
Microsoft could improve by offering recommendations for domain spoofing attacks, especially scenarios where DNS records like SPF, DKIM, and DMARC are not properly published.
There is a different console for different things; I just want one consolidated console.
 

Setup Cost

Fortinet FortiMail offers flexible, cost-effective pricing from $28,000 to $100,000, influenced by features, company needs, and regional factors.
Enterprise users find Microsoft Defender for Office 365 pricing complex but valuable due to integration with Office 365 features.
Fortinet FortiMail is considered overpriced by Indian rupee standards.
We've likely saved 30% of costs.
Money-wise, it is a part of the Office 365 suite, making it slightly more expensive compared to Trend Micro.
Microsoft is quite affordable with a lot of features available for any size organization.
 

Valuable Features

Fortinet FortiMail offers advanced spam detection, easy management, comprehensive security, scalability, performance, and cost-effective email filtering with real-time updates.
Microsoft Defender for Office 365 offers comprehensive security with real-time updates and automated threat response, enhancing multi-platform enterprise safety.
Its threat detection capabilities have been beneficial.
The most valuable features are Fortinet FortiMail's ability to protect from advanced features of email-based attacks, including protection against ransomware and malware attacks.
Fortinet FortiMail offers capabilities like settings for mail delivery, mail filtering, spam controls, and email bursting prevention.
It ranks the threats and allows us to prioritize those hitting us the hardest, such as email threats.
It provides end-to-end visibility on email threats such as phishing, extending beyond Exchange Online Protection.
The value of the DLP feature is significant to us because we have internal data, sometimes sensitive, and the users may not always be aware of security and privacy, which might lead them to send out information mistakenly to external parties.
 

Categories and Ranking

Fortinet FortiMail
Ranking in Email Security
6th
Average Rating
8.6
Reviews Sentiment
7.0
Number of Reviews
64
Ranking in other categories
No ranking in other categories
Microsoft Defender for Offi...
Ranking in Email Security
1st
Average Rating
8.4
Reviews Sentiment
7.1
Number of Reviews
52
Ranking in other categories
Email Archiving (1st), Advanced Threat Protection (ATP) (1st), Microsoft Security Suite (11th), Secure Email Gateway (SEG) (1st)
 

Mindshare comparison

As of May 2025, in the Email Security category, the mindshare of Fortinet FortiMail is 4.9%, down from 5.9% compared to the previous year. The mindshare of Microsoft Defender for Office 365 is 12.9%, down from 18.3% compared to the previous year. It is calculated based on PeerSpot user engagement data.
Email Security
 

Featured Reviews

MOHAN SUKUMAR - PeerSpot reviewer
Secure email management improves through advanced filtering and dynamic virus scanning
Fortinet FortiMail offers capabilities like settings for mail delivery, mail filtering, spam controls, and email bursting prevention. It also allows for email forwarding, dynamic filtering, and scanning based on virus signatures. I can set varying levels of security. The tool is flexible and provides essential features for mail security and management.
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.
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Top Industries

By visitors reading reviews
Educational Organization
42%
Computer Software Company
9%
Financial Services Firm
6%
Government
4%
Computer Software Company
16%
Financial Services Firm
9%
Manufacturing Company
8%
Government
6%
 

Company Size

By reviewers
Large Enterprise
Midsize Enterprise
Small Business
 

Questions from the Community

What is your experience regarding pricing and costs for Fortinet FortiMail?
Fortinet FortiMail is considered overpriced by Indian rupee standards. My organization is not profit-making, and academic pricing is required, but it may not be available for security products like...
What needs improvement with Fortinet FortiMail?
Fortinet FortiMail should keep pace with features offered by cloud-based services like Google and Microsoft Outlook. Additionally, the transition from on-premises devices to virtual appliances may ...
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...
 

Also Known As

FortiMail
MS Defender for Office 365
 

Overview

 

Sample Customers

Magromer Cueros y Pieles S.A.
Microsoft Defender for Office 365 is trusted by companies such as Ithaca College.
Find out what your peers are saying about Fortinet FortiMail vs. Microsoft Defender for Office 365 and other solutions. Updated: April 2025.
851,491 professionals have used our research since 2012.