Other than better mobile browsing, I adore IB and vBulletin.
They leave us the hell alone and let us do our thing. That's pretty awesome. They are not trying to grow their business into a charter airline company or a seminar company. They give us our playground and we play. Good times.
I think MilePoint and the XenForo platform are a bloody mess and nearly impossible to navigate. All the bells and whistles distract from the useful information. I would strongly resist moving to a platform like that. And if vBulletin is headed that direction in 4.0 then I say keep delaying implementation PLEASE.