I've done Insanity and I'm doing P90X now. I think P90X is much closer to what you want than Insanity. I love the Insanity program, but it is not really designed to increase muscle mass. You pound the same muscles almost the same way every day. Some muscle groups are almost totally neglected (traps, lats, biceps). It's an incredible program for developing a high level of cardiovascular proficiency and as well as speed and agility. It's also a big character builder. It will not make you particularly muscular, though. Good luck!
