I read a few years ago that studies were done and they concluded that front squats didn't hit the quads any more than back squats. the researchers hypothesized that people believe their quads are worked more with the former because of the increased strain on the cardiovascular system when front squatting (due to the effort needed to hold the bar across the shoulders, instead of letting it rest on the back). i personally like back squats better, so i always start my leg workout with those. i will occasionally throw in front squats at the end after squats and presses though, cause they're a tough movement that is fun to do-and not to mention, they still work amazingly well.