That is very much the question, as WordPress 3 finally gets its first point update to 3.1. Are there any significant benefits over the 2.9 branch? Interested to hear any and all viewpoints, along with any upgrade horror stories.
(Incidentally if you came here because you thought this might be about me considering moving to the Three mobile network... I've been there in the past. It's a dark place. I'm glad I escaped.)