If you plan on a fair amount of Hilton stays in 2012, I'd say the extra 25% bonus points could be worth it (25% vs. 50% bonus for gold/diamond). I haven't been able to funnel all my stays to Hilton this year and will likely be dropping to Gold next year -- and that's about the only real change I see.

I don't have to do it often, but I do like the quicker customer service from emailing the diamond desk. I remember before diamond that getting an email reply was hit and miss.