Thoughts on bench press: glute drive or leg drive?

Mark Bell talks about glute drive in one of his videos on YouTube.

Basically before you push the bar off your chest in the bench press, you pretend like you're trying to crush a walnut stuck between your butt cheeks.  When you do this, the bar seems to according to Mark Bell "magically levitate off your chest".

The legs and feet are just there to stabilize you while you press, and there is a significant amount of arch applied to the lower back when applying a rock hard contraction to your butt so be mindful of that and keep your lower back as flat as possible. Otherwise you do risk suffering a sore lower lumbar region after you workout.