I have Insanity. I haven’t used it because I can run 5 or 6 miles with no problem, but I couldn’t make it through the first 10 minutes of Insanity.
Ugh. I really need to bust out that set of DVDs & get moving. Moo.
I know a guy who tried insanity. He lost about 15 pounds (he wasn’t really overweight though anyway) but experienced very little muscle-mass increase.