Hi, personally I am not a fan of Xenforo, but I may come to like it as I get used to it.
To make the transition as smooth as possible I would just suggest making sure the features of the old VB system as as closely re-added as possible. Such as groups, maybe seeing who your last visitors to your page were.
I'll be honest... I'll really miss friends. Because that's how I made many good friends on here. I had a lot of really good chats started by requesting people's friendship. Now it seems that will be gone... R.I.P