More isn't better; better is better. I emply both full and parallel (as well as those a touch over parallel) squats. I am a big fan of full squats, but think the important thing is that you put a heavy bar on your back and go deep. I really like using both to mix it up. Especially if I have some minor injury (besides knees) then doing the full squats lets me use lighter weight for a bit. All good tools.