IMAP clien for Emacs?

[fsu]

Hi,

Currently I am running mutt in an OSX terminal as my email client
with Emacs as the mail editor. Even though I like mutt a lot for
speed and imap support, I would prefer an IMAP client in Emacs to
avoid the endless switching between the apps, better customization
through lisp and being able to read mail while replying to messages.

I have looked at three options so far, but would like some guidance
on which one to use (gnus, vm and wanderlust).

Important to me are:

- Speed!
- Filing in IMAP mailboxes
- Copying sent mail to IMAP mailbox
- CRAM/MD5

and while traveling 
- Partial downloading of large messages
- Disconnected operation

Any feedback is greatly appreciated.

Regards,



Frank