I've done the full Insanity program a couple of times, usually once or twice a year. Gives my legs a break from running for a month or two

I loved it! Haven't done it since starting T (I'm faab), but my results included putting on lean muscle, trimming the abs (Insanity did great things for my abs), and tightening up all over. Not to mention the workouts made me feel great. They pushed hard enough to get an endorphin thing going, but weren't so long that you felt like you were scheduling your day around working out. I didn't lose weight on Insanity, but I have a low bmi and didn't have weight to lose.
Anyways, have fun! I think it's a great series of workouts because it really is full body (as your post- fit test soreness probably indicated, haha).