It's hard to get though, and that was by the truest statement I've seen on these forums in a while.
I've only ever used burning board once, and it was amazing.

But, in the category of Free Software - honestly, if you know how to customize it right, MyBB is the way to go, whenever I'm broke and have no software I use MyBB - it's the best Free Forum Software in my opinion.

Edit:
vBulletin, it's nice - and my opinion for a long time is it's really overpriced, and I'd for sure rather pay for MyBB then vBulletin.