First. Unofficially... how stable is this beta? I run a simple gaming forum which is up to about 100k posts and generally has around 60 active members. Not a large forum but it's contents are very precious to me. I know xenForo's staff can't guarantee anything in a beta stage but can you customers comment on it's security? Is it at the "a little buggy" stage or "oh gawd it corrupted my database!" stage?
Second. Can you set different templates/skins for different parts of the forum as you could with vB? As in a holiday sub-forum would have a holiday themed template but the rest of the forum would look normal.