Replying both to you, and GP.
As a recent vB admin/installer (started 4 years ago), I have good things to say about it.
I started with the late 3.x (3.8?).
Then immediately migrated over to 4.0 when it came out.
Have always done upgrades of v4 within 1 week of them coming out.
Honestly, between vBulletin.org and vBulletin.com's support, it's awesome.
I was amazed you said their support wasn't good... because I have always had every question answered, and problem solved.
The latest vB 5, well... yes, it's still in Beta, and I haven't even tried it.
When the release actually comes out, I'll probably upgrade in short order.
I will admit that the licensing thing they did was a mess.
To get over it, I just paid whatever and got done with it.
Yet from what I read, yes... it was a mess, and a screwing to previous loyal customers.
One the other hand of all of this, if the guy is starting out from scratch his forum installation, then he shouldn't mind the quirks of the new vB.
Personally, I chose vBulletin because the best communities I had been part of have been running on vBulletin.
Good discussion guys =)