The original Nautilus compound leg machine was one of my all-time favorite machines. Negative-accentuated leg extensions followed by leg presses to failure left me immediately hobbled and sore for days.
But the buttocks are the stronger muscles in a leg press. They should be pre-exhausted with the old Nautilus adduction/abduction machine.
Imagine a proper double leg machine, a adductor/abductor combined with a leg press.