I bought a few good ones in the past, it's what brought my 'rinky dinky lookin' proboards forum to a decent amount of success, which lead us to move to paid hosting and a better software.
I honestly reccomend them for new forums. Ad forums are good to get the word out, but you're REAL audience is not looking for you on ad forums, they're using search sites to find what they're looking for. and good backlinks using generic target phrases for your site content makes wonders happen.
Ex. I'd never use my site name, super smash bros domain ... because that's NOT what random people on the internet are typing into google. I use common search phrases like "smash bros forum" "smash bros wifi" "nintendo smash" etc.