When comparing Mail.app vs Microsoft Outlook, the Slant community recommends Mail.app for most people. In the question“What are the best e-mail clients for macOS?” Mail.app is ranked 5th while Microsoft Outlook is ranked 15th. The most important reason people chose Mail.app is:
One thing Apple does well is to integrate its apps and hardware. The mail app is no exception. If you must be in the hermit kingdom, at least take advantage of the (often excellent) features provided.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Integration (with other Apps/Hardware)
One thing Apple does well is to integrate its apps and hardware. The mail app is no exception. If you must be in the hermit kingdom, at least take advantage of the (often excellent) features provided.
Pro Will probably be enough for a sizable chunk of users
Since it's the built-in Mac email client and is quite complete feature-wise, most users will not really need any other third-party applications out there. Mail.app should be enough for their needs.
Pro Easily annotate pictures or sign documents inside the client itself
Mail.app has powerful markup tools which let users add annotations to images or even sign documents they got through email without ever leaving the client.
Pro Smart folders on steroids
- You can choose out of tenths of mailheaders (several hundreds including virtual headers)
- "<header> is (not) in <folder> <header>" operator which enables you to do cool filters
- Each smart folder can have smart subfolders by an user definable key
Pro Shows threaded view with snippets in middle panel
Pro Can be easily extended
If the basic features inside Mail.app are not enough, it can easily be extended through plugins to add new features.
Pro Good built-in calendar
The calendar includes agenda, day, and three-day views.

Pro Integration with calendar and tasks
Quick conversion of a received email to a task with the deadline.
Pro Fun to use
clean and smooth experience, very nice and i like it.
Pro Smart lookup
Smart lookup is a feature where the Bing search engine is bundled in the app to allow users to automatically search for relevant websites, information and images based on the word highlighted by users, without need to open external browsers. The results will be shown on the right pane of the window.
Pro Priority messages
Microsoft Outlook comes with feature called "Clutter" to filter out incoming email based on the priority of the message set by user. User will be alerted when the high-priority message is incoming, whereas the low-priority message will be put in a separate folder.
Pro Attach files from cloud
Microsoft Outlook allow users to directly attach an attachment directly from cloud services without need to download an entire file before attach to the intended e-mail.
Pro VBA macros
Pro Conditional formatting
Pro Cloud
can attach files and use cloud, very good.
Cons
Con No option to snooze emails
You can not snooze emails to view later. This makes it hard to keep the inbox clean at all times since you have to read every email and choose to delete or keep them the moment they arrive to do so.
Con Missing lots of advanced features
Out of the box, Mail.app may not have as many features as some other options. This can be mitigated with plugins though. But that is not a perfect solution since third-party plugins may not be very reliable in the long run.
Con Really bad reliability
Database engine gets stuck consuming 100% of one core; crashes; a 40GB log file has been spotted.
Con Updates may break plugins
Apple is known to make API changes to Mail.app when updating which break a lot of plugins.
This can be very annoying for users whose workflow heavily relies on plugins, since they have to wait for plugin developers to make the changes needed to fix any issues brought by the update.
Con Poor performance for some users on El Capitan
Con Ugly
Con Poor calendar integration in exchange mode
Con It's from Microsoft
Con Rather buggy
Con Crashes frequently
The only issue with Outlook 2017 is that when the Mail folder increases in size, it sometimes crashes for no reason it, causing loss of data.
Con Categorize email IMAP not good
Con Frustrating user experience
The "Clean Interface" approach means that normal and necessary user interface elements have been removed, such as certain scroll bars, and even the "replied to" indicator. This program becomes more frustrating with each new update.
Con No unique Inbox / global folders
Con No portable bundle available
Con No aliases
Outlook does not support email aliases other then outlook aliases
Con The UI is outdated
Con Only available for Windows
