Did the complete program a few months ago with the wife, then went straight on to a weight lifting program. Started eating right/more (as I was eating decent food but nowhere near enough) after poor results half way through.
So, 60 days of Insanity (with a few missed days due to work, and the odd alcoholic blowout), and now about 6 weeks of lifting 5 days a week and I've dropped 17lbs so far. A decent rate of weight loss, if not staggeringly impressive, but the change in my actual stature is very apparent, especially the midriff. I've developed visibly muscular quads too, and am definitely stronger.
I think it's a great program... really knocks the hell out of you and, to be honest, if I hadn't taken on the challenge of doing something so extreme I would probably have just kept going the way I was. Now, I'm really paying attention to what I put into myself, sticking to exercising rather than being a lazy piece of crud and I WILL NOT STOP until I've reached my goals.
I won't allow going through 60 days of that nightmare to have been for nothing! Shaun T is one hell of a motivator, too -- something which is incalculably essential for keeping my butt off the sofa. So yeah, my personal experience with Insanity has definitely been a positive one. Are you gonna start it as a fat lump and walk away an Adonis after two months? Of course not. Think realistically.
Anyway, once the current lifting phase is done, I'm heading back to doing an Insanity and lifting hybrid for a while to see how that goes. Then might try The Asylum or P90X.
If all goes to plan, when I'm eventually happy with where I am I would like nothing more than to meet Shaun T and thank him personally for turning my life around. Only about 50lbs to go! LOL.