I'm afraid to disappoint.

These words are marketing blurbs, like "new and improved" or "now with zest appeal".

Generally:

GFE indicates that the gal will kiss and perform BBBJ.  It is also to be hoped for that you will get MSOG as well as your full hour and that she will be at the very least cordial towards you.

PSE indicates anal, BBBJ and hopefully COF.  Whether any of the other features mentioned in GFE are included is not as clear.

Many gals (I'd say the majority of the ones I've met will incorportate all of the above (except perhaps anal.)

I hope this helps resolve the dispute.

Now go and have make up sex.

As has been stated there is no one defination for each.  Sometimes review sites may impose their standards for reviews but the ladies each may choose to interpret GFE or PSE differently.  
In MY opinion (add a buck & you may get a coffee somewhere)
GFE:  means she will kiss & cuddle with you & make you feel like (for the time in question) a girlfriend would make you feel.  The ladies are so skilled at this illusion that guys often fall for them...  

PSE:  is more active, more positions, usually includes anal...  but does not offer the cuddling.  Like living out the fantasy of being in a XXX rated movie.

I'm sure others will disagree but I just read the text.
skb

What encompasses GFE and PSE is very subjective. Thats why dealing with the reviews are best and not just trust those terms.