My paused box squat slightly below parallel (using a regular bench from the DB area) is easier and stronger than my regular squat. I also don't rock back and forth for momentum.
This is true whether it's high bar or low bar. Maxes are about 335 high bar regular and 355 low bar regular, with box being 20 lbs higher for each, same stance. I realize using the box as a trampoline would make the max go up but I always pause slightly.
I will try to get a video up of both lifts asap.