GFE - like your GF, typically includes DFK, BBBJ. Step above your vanilla fully-covered providers that basically get you hard, insert & cum.
PSE - Has come to mean various things over the past few years, but generally more like a porn movie. Action might be a bit more hardcore - face fucking, cumming on her face, rimming, pumping hard, etc. Of course, always respect the provider's limits and don't hurt them.