I'm just sharing my observations after looking at most (all?) of the forums online that I could find. I used them by joining as many as I could, and then made the choice about what I'd put on my sites.
I am a programmer (20+ years worth), however I am not interested in programming everything on my websites.
I also run a niche site that will never have high volume, however my users are also not computer literate, and so I needed something easy to use.
vB met my needs, with a few minor exceptions that I hope will be addressed in v2.1.
It looks like phpBB 2 will be getting some nice features in the future that will make it even more attractive.