Since I will be starting fresh with this install and not need an importer I may just run the beta live. I don't expect too many people to register, so I hope my forum in production will be a great bug finder for the XenForo team. I hope they just don't get sick of my reports .
On vBulletin, Flashchat takes info from your database, so that when you're logged into vB, you can go right into chat if you wish, no need to log in to the chatroom.
It has it's own skins tho, doesn't use the forum skins. It sits right on your forum, meaning that when you open the chatroom window, you still have your forum in the background so your can both browse your forum, and chat in the chatroom.
He has flashchats for IPB, phpbb, smf, mybb, vB, etc. I'm hoping he'll do it for XF as well.