I consider them to be a grappling-centric MMA gym: their BJJ is much better than their striking program. Eduardo "Anjinho" Baiao is in charge of the BJJ/MMA program, and he is a super great teacher and a really generous guy (he holds no knowledge back when teaching). Their other instructor, Jackson, is an excellent teacher as well. The gym is independent but has many connections with Ralph Gracie; they're more or less on friendly terms even though they're not officially associated.
The Muay Thai program, on the other hand, I'm not such a big fan of. Guys from World Team USA are in charge of the program, and I'm not a fan of their style. They say it's authentic Muay Thai, but it really isn't if you go by stadium-style MT as what's "authentic" these days. They're more of a Dutch style, surprisingly, and they have some interesting if idiosyncratic tendencies, but the head striking instructor Victor is a pleasant if introverted guy. He's a great pad holder though, so if you have a striking base, it's awesome working with him.
The facilities are SUPER nice there. LOTS of mat space, a full-sized octagon, about eight heavy bags, and a great heating system (a must in SF haha)! Parking can be tough though, since there's only about 5 spaces out front, and the neighborhood can be a little busy/dicey at night.
Overall a great place if you want to focus on grappling, IMHO. Good luck!