I like vBSEO very much and it has even helped with getting my adsense numbers up. It virtually has paid for itself in adsense revenue alone.
Especially if your forum is optimized (like JPiC) for adsense then vBSEO naturally will allow for more links on google, which means more visitors & registered Members, which means more potential for visitors clicking on those adsense links.
I think it's a phenomenal piece of software and well worth the purchase price
Jacquii.