I've always loved the leg press and have trained w/ it many different ways - low rep / high weight, silly low weight / silly high reps - e.g. the sled for 4 sets of 200. I've also had to give up on it at various times due to a bruised rib a few years ago and last yr when I messed up my lower back due to rotated pelvis. I was also informed that all my years of leg press may have contributed to some disk degeration in my lower back.
Despite that, I've increased my max for reps of 10 by about 100 lb each year since I started competing due to specific training. Latest PR is 45 x 12 plates (540 lb, excluding the sled) for wide stance, 3 sets of 10 and narrow stance 45 x 14 plates (630, excluding the sled) for narrow stance 2 sets of 10 - no spot, usually as part of 2 super sets of 3 sets each of hack + leg press. HOwever due to more shoulder problems I"m laying off heavy hack and squat, and generally scoping down my lifts. Its not in my goals any longer to go for max weights.