I'm looking at the webpage now. Sounds like it tries to resolve some of the thread locking issues. Not sure I'd use the orgmode -> rich text email feature, but that is pretty awesome. Anything in particular you find superior to GNUS or otherwise useful?
Well, the idea behind mu is to use searches to filter your email
instead of using imap folders. Indexing does feel a little slow
sometimes, but it is far better than writing procmail rules to filter
email.