I thought it wasn’t great at first, but….
I’ve been using it for a while, and I didnt understand the appeal of this app at first. But after reading a bit more reviews and looking into each feature more carefully, I realized it was actually quite useful and capable.
For example, swiping actions in Apple Mail is not consistent with each mail account. i.e. Swiping to the left/right gives me a different set of menu depending on which email account Im checking at the moment. Not so with Airmail. Its integration with many popular third-party apps such as OmniFocus is very handy. And, its search feature, in my case, is noticeably more accurate and consistent than Apple Mail. Slick interface makes it more pleasing to use. Email is something I have to use all the time, so this kind of small details count and Airmails various features come off as features well-thought-out.
Strongly recommended if you do more than casual email.
CyberK.S. about Airmail - Lightning Fast Email