The link to user/community functions are nice, but they are slow (or, too slow for those of us who type quickly). When I type a user name, select it, and hit command-u, the dialog box drops down at normal speed, but when it's dropped, there's about a second's delay before I can hit return to just accept the default. Not a huge deal overall, but a pain when you're typing a long post with lots of usernames.
And all things considered, not a big deal, since I like all the other features of the latest client a hell of a lot. :-)