I do push presses on a regular basis during my circuit workouts and have been told that I should not be doing a couple things that I do while I perform this lift.
1. not to squat as low as I do (bring legs to a 90d angle)
2. not to do the press from behind my neck
I enjoy this lift a lot, I also like to go down to a 90g angle and burst up, using the momentum to push the weight out of the "behind my neck" range and complete the lift with my shoulders.
I rather do the lift from behind my neck because the weight is more stable during the squat and it seems to add more momentum than doing them from the chest. Doing the excercise this way in conjunction with my circuit workouts totally kicks my ass, and I love it.