I have the same question, I am leaning toward Insanity since it's cheaper since I won't have to buy pull up bar and weights. I am 22yr old with about 20 pounds to lose and a full time student. I am pretty active(running), and I have done a month of the Biggest Loser last chance workout but I wasn't seeing dramatic results and I like the idea of having a food plan . SOO my major question is which is better for weight loss?

If you already doing running and not happy with your results go for P90X. You can start just with the bands only that will set you down maybe $20 than add later pull up bar for around $30-40. I notice my biggest results with P90X as per weight loss and body contouring. Insanity I started right after so my results aren’t as dramatic but my cardio, core and stamina are incredible. If you will commit to either one your next step will be combination of both later. Think that you not spending many to do a program but to start and continue better life stile. P90X is easier to adopt and adjust to as a beginner than insanity.

Thanks! Yeah, buying just the resistance bands sounds good, I really don't want to bulk up but rather loose the extra fat around my waist and arms and eventually tone everything else. I lost 40 pounds about 2 yrs ago with just running and diet but now i have been stuck at the same weight and am ready to knock off the last 20.

I ended up doing insanity twice through, and am on my third round, needless to say i love it.
I lost about 10 pounds since starting and a lot of inches and started seeing definition on my stomach. ONce im done with insanity I think I'll do p90x or turbofire or some sort of blend. Each time i fnished I took a break for about 2 weeks and did other workouts(turbofire,Biggest loser,running,hiking) . I really love the intensity of it.
The second month is killer !