I made the move to Xenforo a fortnight ago and today I got a weird example of an SEO boost.
I made a post some months ago moaning about the service I received from a company hired by my letting agent to chase up my references and stuff. Since moving to Xenforo, that webpage has gone to number 4 in Google's ranking when you search for this particular company just by their name. A fact I was unaware of until one of their representatives sent me a text message today, asking to have a conversation - after calling me when I was working.
Though I've not spoken with them yet, I'm guessing they want to convince me to remove that page..