Top Law Schools

How important is the PS with regard to admissions?

Not that important. Unless it is egregiously poorly written (which will affect you negatively), it won't really do much.

It's a number based game.

It probably means a little more for schools with a "Why X?" section.

pretty important if you're a competitive splitter (one of GPA/LSAT above median, another below median).

By competitive I mean 3.3/171 for Penn, not 2.5/180 for Penn or 4.0/150 for Penn.