[tschai]

Looks better than bbPress and Vanilla already, which are missing very basic yet trivial forum-features.
But unlike those two XenForo will cost somewhere $140 already as a Beta and a minimum of mods, naturally.

However XenForo looks like 'vBulletin finally embracing web 2.0', which was what I was looking for in vB4.0...and did not find.
Although they could and should have implemented also out-of-the-box:

1. A Portal/homepage (like vBadvanced, not vB4.0) (although they do have a mysterious 'home' tab)
2. A Mobile/Tablet version. At least a coooperation with companies like'Ttapatalk'!
3. One (or more) sexy freemium templates, by one of those Wordpress templates makers. Anyone.

Then $140 would have been fair and they could have easily asked more. Much more.

Having said that, like many I have so many (self-made) mods, tweaked, optimised...I don't know whether I can switch at all.

But it does look very promising, despite some nay-sayers in this thread...I keep watching the developments and I am impressed unlike with the underwhelming vB4.
It'll be my first choice whenever I might be ready to upgrade my good old loyal vB3.6...kudos to them.