I have seen quite a few girls advertising Pornstar experience.  How does that differ from a normal experience?

But in theory, the whole tenor of the session should be different.

Whereas GFE is somewhat about kissing, hugging and cuddling, PSE is about wild abandonment.  Things like COF and DT are also more likely with PSE, but sometimes those come with GFE.

Some gals offer both, with PSE often another $ over the GFE, but there is a lot of variation even there.

As always, use the reviews to evaluate the kind of session you expect to have.

face fucking, sometimes BBFS, ass play, rimming etc.

It's NOT just Greek. That's a gross over simplification.

just the first line.