I can't really do that because I work here, what a vendor is looking for is a bit different than what a member is looking for.
for example
safety- how well mods and admin protect everyone
general attitude- I couldn't imagine paying to be on a forum where people have an eroids or meso attitude
integrity- are mods and admin working with or for sources in a way that make them bias, I know where we have all seen that, It's ok for mods and admin to rep but not in a way that they can take advantage of their positions and cover up trouble. As far as our company, I would prefer that nobody deletes a thread someone makes to say we suck or messed up, I don't care where they post it, I would not want them chastised, they paid so they can talk about us and our shortcomings any time.
source to member ratio- if there are 15 aas sources and just a few hundred active members it's not worth paying to be there every month, we are on one forum with about 30 sources and 150 active members, they make up for it by charging only $200 per year so it balances out. Letting in just anyone and flooding a board with sources takes away from it's quality and trust rating.
I would like to see forums have a transparent vetting process, maybe the source needs to have a certain amount of reviews across a few boards or a few guys to vouch.