So far, I haven’t heard many big complaints about WordPress 2.5. There are lots of confused people out there trying to get a handle on all of the changes, and many errors they are having are of their own creation, but theme, plugin and other major errors seem to be relatively low for a release of this magnitude. Some broken plugins, sure, but other than that, I am very impressed.
It looks to me like the extra time was well spent. The next big area of concern for most people are plugins. I know many people are working on updating their plugins for WordPress 2.5, and hopefully most of the major plugins will be updated in a short amount of time so that everyone can bask in the newness of the WordPress 2.5 administration panel.
My best advice is to throw money at problematic plugin authors to make it worth their while to get their new release out today, rather than “when they can”.
Let me know if you come across any major WordPress 2.5 errors. Keep checking the WordPress Forum as well for support.