I love mutt, and I'm really hoping mutt-kz replaces vanilla mutt. I think that mutt-kz + isync are a great mail suite.

I'm missing address completion a la gmail from notmuch, though. This is a feature mu (which can also be used as a backend, like notmuch) has implemented. I've never understood why notmuch always relied on ugly and slow hacks for this.

Incidentally, I type my emails in emacs, but I don't like using emacs as an os, so it's just my email composer.