When comparing Mail.app vs Opera Mail, 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 Opera Mail is ranked 11th. 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 Intuitive user interface
The design of the UI in Opera Mail is clean and intuitive, making for an easy to use client.
Pro Very efficient search
Be it the subject or the sender, it is very fast and accurate.
Pro Opera Mail CAN BE set as default email client in Windows 8 & 10
Pro Automagic smart filtering
After a bit of use Opera learns what e-mail belongs in what folder just by previous usage. This makes for a convenient way to have e-mails filtered without having to manually mange every e-mail.
Pro Free and based on Mozilla code
Opera Mail is completely free to download and use and it is based on Mozilla's code, which is what makes it a bit similar to Thunderbird in looks and function.
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 Being discontinued
Opera Mail will be end of lifed per Opera website
Con Very limited feature set
Compared to Thunderbird.
Con Sync is slow
Opera tends to be slower on e-mail sync when compared to other popular clients.