I've been wearing both for a while now, and there are a few differences;
The standard XX2 has a sockliner with slightly raised sections at the ball of the foot and the heel, as well as triangle shaped ventilation. The PE has a standard sockliner.
The lacing system on the PE allows for a *much* tighter fit without any lace slip in the laces - unlike the standard XX2.
The toe area on the PE feels a little more narrow, and just slightly more elongated. My experience was that it's not to the point of different sizing being needed from the standard XX2. The upper on the PE appears to be Optimobuck(?) fairly sure it's standard nubuck on the first XX2.
The front of the midsole feels a little thicker on the PE - also it's midsole doesn't seem to crease so easily.
The Air unit in the PE appears to be glued down to the inside of the outsole. After cutting the lining, i had difficulty removing it, and didn't want to force it.
Having Just an air unit for the heel isn't that bit a sacrifice - a large chunk of the heel is phylon and i can't feel much of a difference between the two units in the standard XX2.
Air Jordan Retro: You can't go back.