I'm using it on a forum, and I must say it exceeded my expectations. Is it better than vBulletin? I wouldn't know; I've never ran a forum with over 50 posts with vBulletin. You can always start out with vanilla, and if you need more power, different layout, or whatever the case may be, you can switch to vB. There is a plugin or something that supports the db transfer from vanilla to vb, just google it.

I say go for it.