45 degree leg presses are potentially a nightmare for the L5 S1 disc, Dr Stuart McGill has written about this.. same with any kind of crunch or situp.
Good leg presses like the nautilus xpload horizontal plate loaded one, are just as effective as squats with less lower back trauma. You can do higher reps without risking snapping your shit like you would with squats when the stabilizers and back fatigue before the legs.
I love squats but they're not a make or break exercise. I did belt squats and leg press for a year and my legs lost no size or strength.
anyone spouting broscience about hgh release, squats build the arms etc can still go fuck themselves.