I just upgraded to WordPress 2.5. Went very well, with the exception that the Popularity Contest plugin causes a fatal error and won’t load. The interface changes take some getting used to, mainly because things moved. It’s nicer overall. I’m looking forward to using the new media/gallery features.
The Automattic Subversion repository doesn’t didn’t have a 2.5 tag, so, being impatient me, I jumped to the development trunk. The Popularity Contest issues might be because of that (it was listed as compatible with 2.5), so I’ll try it again after they get a 2.5 tag out there.
To the WordPress 2.5 team I say: awesome job folks!
Update: http://svn.automattic.com/wordpress/tags/2.5/ exists now. Yay!