I've used them both. The one on the left as you land 13 had a ramp fee if you didn't buy fuel; overnight fees wheren't cheap. Fuel was expensive. O.K. FBO, but a little older.
Across the field, right landing 13 used to be Million Air. Nicer, newer facility. They were out of 100LL the time I stopped and not very apolegetic about it; long line of jet folks trying to pay their bill and leave. (This was right after the change over and it all may have improved now.)
If you need PSP, be prepared for it to busy and expensive--like any big city, close in airport. There are more affordable alternatives if you don't want the convenience of being right here. But if you need to be in the middle of things, very nice facilities, very nice staff. No fuel discounts I could wrangle <g>
Best,
Dave