When comparing MailMate vs Unibox, the Slant community recommends MailMate for most people. In the question“What are the best e-mail clients for macOS?” MailMate is ranked 1st while Unibox is ranked 15th. The most important reason people chose MailMate is:
While most email clients support searching content from their To, From and Cc fields, MailMate lets users search down to the different sections of these fields. For example, you can search for the address only, or the name only, or even any one of the embedded headers. Subjects can be searched by prefixes, or by specific words which may be contained within and so on.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Extremely powerful search features
While most email clients support searching content from their To, From and Cc fields, MailMate lets users search down to the different sections of these fields. For example, you can search for the address only, or the name only, or even any one of the embedded headers. Subjects can be searched by prefixes, or by specific words which may be contained within and so on.
Pro Markdown support
Markdown is a way to format text quickly using only the keyboard. Different text characters create different text: for example, putting asterisks (*) around a word or group of words will italicize them, while double asterisks (**) will bold that text. Markdown is a basic formatting system that can then be adapted to HTML or other formats.
Pro Clean, no-fuss interface
MailMate's UI is very basic. The icons are limited to some default MacOS standard folder images and the interface is very clean and simple, showing only what's needed without any fuss or distracting colours. Instead, opting for a mostly grey interface, with a sprinkle of some other colours here and there.
Pro Reliable
Both MailMate's speed and performance are highly reliable.

Pro Keyboard focused
MailMate is extremely keyboard-focused. Almost every action can be configured to be achieved through a key combination in the settings. With the help of the keyboard shortcuts you can easily navigate through thousands of messages to find the one you need.
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 Great documentation
The official documentation for MailMate is very thorough and helpful. It covers all options and features in a clear and efficient manner.
Pro Simple, clean interface
Unibox's interface is very clean and easy to understand. It has a classic two-pane interface with all users that have sent emails on the left side and any email currently being read on the right.
Every UI element is only visible when needed. For example, every time you hover on a discussion the trash can, which is otherwise invisible appears.
Pro All emails are sorted by contact
Pro Makes it easy to keep track of different discussions
Unibox groups different emails by user instead of subject. This makes it easy to keep track of messages sent to a particular person and to keep track of different discussions.
Cons
Con Hard to master
For occasional users who only write emails to friends and loved ones, MailMate's features may be a bit of an overkill since it's designed for power users who spend a lot of time writing and reading/organizing emails.
Con A little steep price
$50
Con Not so "native" Gmail support
Because it's more IMAP native, and Gmail uses some non-native IMAP stuff (according to MailMate's documentation).
Con No POP or Exchange support
MailMate supports IMAP and IMAP only, there's no POP or Exchange support.
Con Sends empty emails
Other than syncing issues and displaying wrong badge numbers, Unibox sometimes sends empty emails to people in the user's contact list, which is quite annoying.
Con A number of recurring issues
There are some recurring issues with Unibox: these include the sync dropping and e-mails not reaching their destination.