THere are 2 differences that I can see.
PS is more strength orientated than endurance. Ita also has a floor work section that is missing in LL.
LL is pure endurance, tough, quick and dirty. A 35 pound barbell and dumbells are all you need.
PLB has floorwork section with ball: the pyramid style allows you to go quite heavy also, depending upon wn\hat your starting weight is. So, for squats you might use 35/40/45/40/35. Or higher still, depemding on your abilities.
I would say that LL is comparab;e to the standing work of PLB. PLB in its entirety is comparable to PS legs.
Clare