MDS was awesome. I think it was a great prep for the upcoming I, Bodybuilder.
My training partner put on 25lbs (I'd guess 5lbs of fat) but he had little bodybuilding type lifting experience (<1 year weight training exp in total). I only put on 10lbs (3lbs fat according to my bf scale) but admitedly I didn't eat near enough.
Put 40lbs on my bench press, 35lbs on my deadlift, 35lbs on my bent row, and got by back squat back up to my old PR of 250lb (couldn't touch that in four years since training Max-OT style).
Negatives, I'd say don't do this unless you're eating enough and loaded on all the supps he suggest. Weirdly, I wasn't terribly sore, but I attribute that to tons of foam rolling and the supps (SWF, Powerdrive, Beta 7, Creatine, GPC, and later Curcumin).
My joints did take a pounding and I accumulated my fair share of annoying little injuries that I'd expect from a 12 week program (wrist, shoulder, clavicle, low back tenderness). I'm happy to be away from that style of lifting for 6 weeks (training athletic style right now; Parisi mixed with Twist).
Biggest positive that my training partner agrees with is that if you're not 100% confident doing a deadlift, a squat, a bench press, a bicep curl....you'll feel extremely confident in form after the program.