I've done my homework on just about all of these places so I'll throw my hat in:
Full MMA
Ultimate Fitness: Trained there for a few weeks last summer. Overall I liked it (espescially Urijah's sub grappling classes), the muay thai classes that I took were alright (I never really got a chance to take the straight jiu jitsu classes though). Too expensive for me (if you do EFT it's
slightly cheaper, but I've had some bad experiences with EFT)
Ultimate Training Center: I haven't really heard too much about them good or bad. Scott & his brother work out at the CalFit that I go to. I've seen it and it looks nice though, I'm not 100% but I believe it's cheaper than UF.
Marinoble's: I have a buddy that trains MMA there and I'm also somewhat familiar with the school due to my training time at Niavaroni's back in the day. To me it's too expensive for the availability of the MMA classes (or lack thereof). They have good instructors though.
CA MMA Academy: I found this place on the web. Looks pretty big on the website, pretty cheap compared to the above schools.
CA MMA Home
Team Mixed Breed: They have since moved to a bigger facility since the last time that I was there, but the overall impression that I got was pretty good. They're small, not fancy, but they train hard and everyone there seemed to be like family. Price is unbeatable!
Sidenote: There are a lot of other TMA schools trying to pass themselves off as MMA schools now (i.e. a school that has been a Kenpo or Tae Kwon Do since forever but they've somehow reluctantly added grappling), I'll leave them out for now.
Striking
Niavaroni's: I trained there in 99-00 back when they had two locations. The cardio conditioning that I got there is hardcore for sure, Nasser's expertise is full contact kickboxing (no kicks below the waist) and boxing, but he is very familiar with muay thai. Prices have pretty much stayed the same since I first trained there.
Muay Thai Thai Boxing: Andy K is the only authentic Thai Muay Thai Kru around (that's has his own school, there are a couple of good trainers at other schools). My boy used to train there (not sure if he still does), I trained there with him one Saturday a few months ago. I liked the instruction and the way the classes are run, but it's way overpriced considering the class availability (again, or lack thereof). The gym is pretty small.
BJJ/Grappling
Cassio Werneck: I'm no grappling expert but everything that I've heard points to Cassio being the best BJJ instructor around here. He's trained Urijah, Scott Smith & Irvin among others.
Groundworks: My buddy that trained at Andy K's trained at Groundworks as well. I've heard a lot of good things about them, but it's a Rickson school so be prepared to pay up.
In conclusion
There are a few other schools in the area but these are the most known IMO. If I had the time & money I'd probably choose between UF & UTC (although Roseville's pretty far from me). I would like to believe that the Muay Thai is a lot better at UTC considering that Smith & Irvin have had a lot of training under Ganyao & Jongsanan Fairtex, but I cannot confirm this assumption. Urijah definitely has the best wrestling pedigree around though.