PLB is, for me, the hardest among the three because of the increasing weights and high reps. LL is the second hardest because of the moderate weight and high reps. L&G is a class all its own. It's "easier" in the sense that you get to use lighter weight, but it still kicks your butt because of the numerous exercises and the fast pace of the workout. I think L&G is more of an endurance test than LL. PLB helped me gain strength, which I needed, and mass, which I didn't need. Nowadays I use a combination of different exercises from different leg workouts. I lost some mass, which was good, and some strength, which was a bummer, but I have nicely toned legs, which I'm satisfied with. As has already been said, what you get depends on what kind of result you're after.
Pinky