As I'm a emacs person, I tried once wanderlust[1] and got hooked up to it. Wanderlust is mail client which supports a wide variety of protocols. For me the biggest advantages are the blazing fast IMAP support and the whole emacs thing (Keybindings, Help (C-h b for all keybindings in this buffer, priceless I have to say), the possibility to run it either in GUI or in a terminal, etc). Recently the devs uploaded it to melpa[2] which makes it even more easy to get started. I would definitly recommend it, to people who are already using emacs, its such a joy!
What are the bugs you are referring to? I have been using it for a few weeks for a couple of mail accounts without trouble so far. It could probably be faster though (customizing 'maxconnections' does help).
It never reliably functioned as a daemon for me. It would just stop checking for messages randomly after an hour or two. And if you give up on it being a daemon, then it's horrifically slow because it's doing full syncs all the time.
I ended up having a script running out of cron that would kill and restart the daemon process every 30 minutes so that I could get reasonably fast incrememntal updates but still have it continue to work properly.
And then it started losing track of what the server looks like. If you delete a label on the Gmail side, then of course offlineimap wants to recreate it. For a little while, it was tolerable to stop offlineimap, delete all the local metadata for a folder, go delete the folder from Gmail, and then restart offlineimap, but eventually that stopped working too, and it was recreating deleted folders on the server that I never managed to find a reason for.
isync just worked exactly how I wanted to after spending a bit of time setting it up, and it's been pretty solid since then.
[1] https://github.com/wanderlust/wanderlust
[2] http://melpa.org/#/wanderlust