I will probably start off with the "legacy" vBulletin 3.8 (which I have installed now and have used for the two tests I've run) as it is mature, and well debugged. There are also lots of "skins" and other customizations available for it that work well. The version 4.0 is indeed so new that it isn't fully debugged, and it is an order of magnitude larger of a script package, in terms of size and complexity, than the legacy 3.8 version.
Just discovered the vBulletin 4.0 attachment screen nightmare this weekend when I attached the VIN PDF piece to my reply. Wow, what a clusterfuck that was, doing a simple attachment!!
Almost makes me want to stay with the tried and true phpBB ... if I wouldn't have already have pounded out the money for the vBulletin (which isn't cheap, by the way) I probably would. My hosting bill is coming due here for early July. That costs around $90 a year. So combined with the vBulletin license fee, at a pro-rated monthly rate, it all comes out to about $17-18 a month. I can start to see why Scott wanted to get sponsors and solicit memberships for his board.
I will never do this for the 500Espot / 500Eboard.com community. It will always be a free service to the community, at least until it gets to the point where it becomes a significant monetary outlay that cuts into my household budget.
Cheers,
Gerry