I am currently using following forum scripts
1. Vbulletin - since 7 years , Have my own owned licence
2. Xenforo - from old team of VB, using since 1 years ( since its a new entry ), my own owned licence
3. IPB - using since 7 years - working for a client on it
4. other free scripts like SMF, PHPbb, mybb etc. etc.
I have used almost all type of forum scripts, I am working on forums since 7-8 years, I know very well about Cons, Pro of each type of free and Paid forum scripts.
also well aware about availability of various resources for all type of forum scripts, message me for more details and discussion