I don't know what kind of GF's you have had in the past but all of mine ex-gf's would do BBBJ, DATY, DATO, DFK, biting, BBFS and CIP, massage, duo showers, fuck in any position I wanted, fuck anywhere I wanted (the best had to be the stairwell of an apartment building and at Golden Ears park on a secluded beach).
To me a GFE SP mirrors all of these experiences except for 2 things:
1) no BBFS or CIP
2) I pay for the right to leave with no strings attached.
Having a real GF that does what I have experienced before is a good way to prevent from becoming addicted to GFE SP's.
IMHO, I have found that pretty much any GF will do these things if you gently nudge them to and if you take the time to make sure they get the big O (via everything, like oral, body kissing, massage, and fucking). The more you know how to make them want to fuck, the more they will do what you want.
It is good to learn these things about women, 'cause I have had GF's with a low libido and always saying "no" but after a little cuddling and a little bit of gentle strategic caressing, a "no" becomes a solid "fuck me know".