Class.. anything with big hodges name on it will be 100 percent legit but youll already know that by now!
Jiujitsu and mtb go pretty good together too. Just turning up to a nice clean room with a clean gi and a bit of water is pretty refreshing and on the flip side the cardio boost you get from riding will do your jj game the world of good.
Most decent clubs will have a white belt class and an advanced class ime. The level of grappling of a lot of mma guys really isnt a patch on dedicated grapplers. Youve just gotta be pretty selfish with your training and avoid the people that you get nothing from or worse, people who have the potential to injure you.
:)