I've just recently started going ass to the floor, after watching Needsize's video clip. I have to say, my quads are sore in places they've never been sore before, and I love it. My heaviest set so far was 225 x 8 reps, and that was harder than 365 for 10 going only halfway down. My knees don't hurt, my back doesn't hurt, and my inner thighs and hamstrings don't feel like they're at risk of being torn anymore. I'll never squat any way but ALL the way down ever again. Also, if you get the same, or better, muscle growth from 225 instead of 400, why use the extra weight?