Your best off using thunderbird, as it is free and has had over a decade of reliable functionality.
If your OCD makes you feel uncomfortable with buggy software, I would strongly recommend avoiding Mac Mail, due to it invariably having faults for the first 3 minor point releases of OS X / MacOS versions.
(Based on the record of problems with 10.7.0 - .10.7.2, etc up to 10.11.0 - 10.11.2 , it is safe to assume this will be the case with 10.12.0 - 10.12.2 )
Thunderbird is effectively a free software version of outlook, in that it does have a calendar and chat built in.
If you need to do PGP/GPG, then you can get the free GPGTools, and then run it with the free Enigmail plugin.
Another worth considering if you just do Gmail, is Kiwi for Gmail. (No, I didn't make it, but have used it previously.)
That is a dedicated app which has Gmail within it and is reasonably reliable for the basics, and does all but PGP/GPG.