I own a vBulletin forum with over 3,700,000 posts and 1,200 members logging in each day.
I don't recommend vBulletin.
Reasons:
- Jelsoft sold the platform to a company called Internet Brands and it's been shite every since. Version 4.0+ isn't a pretty product and it ignited a bunch of drama over the developer's evident disconnection with vBulletin owners.
- You'll notice that most big vB boards out there are still using v3.8.x which is the vB that you're used to. vB 4.0+ is an insulting attempt to catch up with Invision's IP.Board, except their idea of catching up involved adding default, ugly gradients, an unusable templating system, avoiding features that people have come to expect on the internet, and a generally disappointing product.
- The forum software still hasn't really changed from its initial design. You still feel like you're playing with something made in 1999, and your intuition is pretty much true.
- The developer isn't a forward thinker and vBulletin is riding on the slowing momentum of its hey-day in the mid 2000s and the resulting network effect.
The nice things about vBulletin: One of the most familiar forum interfaces out there (not that any alternatives throw anyone for a loop--I'm just scraping the barrel) AND its significant developer and add-on community. But these things don't matter unless you like cruising a list of thousands of add-ons that add zero value to your forum.
Options I recommend, instead:
1.
Rolling your own. This is actually what I'm doing for my next product. I'm designing the forum with Ruby on Rails instead of trying to learn how to manipulate a pre-existing forum. I think forums are slowly dying in favor of more integrated community designs that rock the old message board boat. I have more control over implementing these emerging expectations when I've coded my own forum. I also hate diving into forum platforms. vBulletin burned me out.
2.
Invision's IP.Board. The only other forum platform worth paying for. Very well-coded. You feel like you're working on something that the Wordpress people would make if they entered the message board arena. Not as many hacks as vBulletin, but most vB add-on aren't useful, and many of the good ones just give vB functionality that IPBoard already has, or is trivial to change because IPBoard is easier to modify. IPBoard's admin backend is legendary after working with vB for 5 years. Great performance out of the box. They stay ahead of the curve.
3.
phpBB. Biggest free forum with the biggest community.
4. There are very good forums out there that are shadowed by the prevalence of the big three, but if you are porting over a large userbase, you probably want to use a forum that's easy to google support for. Then again, you aren't going to need this advantage unless you plan on making some heavy modifications to the platform. I'd take the WFers in this thread up on their Xenforo recommendation and try it out. I've no experience with it.