I am a Sr. Moderator at a forum that uses vB, and I participate at another fitness forum that uses vB. They use 2.2.6 and 2.3.0 respectively. I really like this forum with 2.3.3 version. It is quite similar to the forum that uses 2.3.0 but seems even more user friendly.
Anyways, just thought I would show my appreciation for to choice of software and the ease of use!
Actually, there isn't any difference between the different versions. It has more to do with us, as we had 'hacks' to ours to make it a little more friendly. We have quite a few forums in german & english, so I am very well versed in making the forums do whatever I want. Check out http://www.worldfitness.com for a really hacked up version of vB.