I didn't read the rest of the thread but I've used the v-squat, the kind you load with plates not the kind with the weight stack. The main advantage for me is I have horrible lower back problems and the v-squat lets me or helps me keep my back straight, it's kinda like doing a really strict squat on the smith machine, legs out in front back held straight. This past friday I got 13 reps with 455lbs, I go as deep as the machine will allow which is about parrellel, maybe a little above, my back hurt a little when I was done but if I tried to do that with free weights I wouldn't be able to drive home cause my back would be hurting so bad. I try to keep my legs pretty close to focus on the sweep of the quad, it's kinda like doing a straight up and down hack squat.