Kaiten supports multi-folder sync, flagging, filing, signatures, bcc-self, PGP, mail on SD, multiple identities, search, configurable notifications & more!
Built by K-9's lead developer, Kaiten is simpler, easier to work with and a whole lot prettier. Frequently used commands are now available in the application's action bar. If you have the screen real-estate, Kaiten's split-screen view lets you see a mailbox and individual messages side-by-side.
Please note that neither K-9 nor Kaiten Mail currently support Exchange ActiveSync.