I run a vanilla board. I think Vanilla is a very complete, fast and stable forum software. The only problem i have is that none of the add-ons i programmed work the way i wanted. This is because the design of Vanilla is extremely object oriented so there are rules that you have to follow.
BBPress doesn’t have that. Instead you have a lot more freedom to do things, and that’s what i wanted, so i’m moving to BBPress.
Of course the object oriented structure of Vanilla is extremely well designed. I just don’t think extreme OO is completely adecuate on this kind of software.
Another difference is that in Vanilla you just enable an add-on and it works. You don’t have to add code nor modify files (again, this is because of the structure of Vanilla. This is a very good feature, specially if you don’t have experience in PHP). In BBPress mostly all of the time you’ll have to modify files in your template to use some plugins (i like this, because i have more control over what’s happening).
In short, Vanilla is excellent, but it’s not for me
I am not sure, but how big is the development community on Vanilla?
I don’t know. But they have 306 plugins http://lussumo.com/addons/index.php?Sort=Recent.
Looking through the documentation, it’s quite interesting but you’ll find writing plugins much more difficult. It really requires you to understand, or at least work with, OO (extending classes and the like), whereas in bb you can do well with just functions.
Vanilla seemed great for a while, but I found integrating it very annoying. Writing your own extensions is extremely hard unless you’re doing something very basic. Having said this Vanilla is good if it can do everything you want straight away. Just make sure you’re capable of theming it properly as it’s annoying seeing yellow posts on every Vanilla install. But their community was very friendly, if a little nontechnical, but this was +6 months back.