I'm not using it for MMA, and the question wasn't how well does it work for MMA. It was just asked if it works.
For MMA no its probably not the best thing by itself. Certain aspects work just fine, plyo and bodyweight stuff is good for folks who don't have access to gyms or weights.
The point of P90x is to just get you in shape. If you want to specifically train for something then yeah you need a more specific program.
Isshinryu Karate 2nd degree Black belt.
Neko-Ryu Goshin Jitsu 2nd degree Black belt.
Jujitsu 2nd degree Black Belt.
Isshin-Jujitsu 2nd degree Black belt.