I've been here for some time, but finally we decided to move our Rock im Park Festival Forums to xenforo. You can see the result here: www.parkrocker.net
We've been using before vbulletin 3.x for several years. And before that even phpbb and others. Yeah, we've now online since almost 11 years, it was founded by myself in March 2003.
It's mainly about the music festival Rock im Park which is actually one of the biggest festivals in Europe. But there are other topics as well, especially Rock Music, Sports, Travelling.
We don't have tons of addons and the design is simple. I know that, but I like it that way and it's easier to maintain. And that's one of the lessions I've learned in the last 11 years...
About the migration which took place this saturday: It was quite smooth. We have about 610'000 Posts in 16'000 Threads and 9000 Users and the standard xenforo importer needed only about 2 hours to import all that stuff. That's really impressive, thanks a lot @Kier and @Mike for such a smooth importer. Only thing that's still needed: The search index is not yet redone. That will happen that night.
My thanks goes also to the incredible Addon and Style Developers! We spent some money on that, but it was very well spended money.