Yeah, there are a lot of people (generally old people
) who don't support the vBulletin 3 Style. I think perhaps only with vBulletin 4 will people like David, when vBulletin 2.5 is no longer supported (although they may stop it with the release of 3.5) change over.
Personally I don't think there is a great deal of change, Vertical Postbit can be used and most of the rest is good. The only serious bit that is bad about 2.5 is the Text Editor. Its crap on 3.5 still, but its not so crap.