Both are excellent leg exercises and one does not replace the other, both styles have their place in a routine.
I often do both in the same day because they both hit the quads a little bit differently...I'd say the bulk of my leg training revolves around these 2 lifts and lunges. I do use other lifts but they do not make up the bulk of the work.
For front squats, I like a slightly more narrow stance, with either a 2x4 or 5lb plates under my heals.
JPM is right about 2 things, elbows must remain up and GM will help with lower back stability. To add to that, HYP-EXT can also aid in this, as well as maintaining a regular ab routine. Keeping your mid-section strong, even while bulking will greatly benefit your training over-all, especially when you squat, do deads, and military-press.