Mainly: I hate it.
There - I said so out loud. May the catharsis begin.
My first reaction to every new Facebook feature is... "How do I opt out?". The ever-raging debate: "To add or not to add family". The most inane and boring things I have ever read proudly displayed as status messages. Photos of everyone from your dog to your grandmother. Gah.
Facebook could have made a really good Addressbook. But then they added some features and blew that chance.
So, my recommendation: Sell all your facebook stock, delete your profile and join the offline bandwagon. But then I'm a cynic. And everyone knows - never take life advice from a cynic.