Great email client

I was using Mailbox before, then went back to Mail.app when Mailbox announced they are shutting down. Airmail looks like it could easily become my main mail app. It has all the features I am looking for, the UI is nicely designed and based on my limited usage so far it seems to be reliable (too early to tell though really).
I was concerned by the fact that the app was constantly using between 30% and 50% CPU, which is just too high for an app that I typically have open all day long.
I contacted the developer about this and got a very fast and helpful reply explaining that this should only be during the initial import/indexing of all my Gmail mailboxes. Right now, it is still working away, but I am hopeful that this high CPU activity will indeed stop once the initial indexing is done.

jaheku about Airmail - Lightning Fast Email, v2.6.1