Ok now I know you dont know anything about GSM, wordlphones nor the APPLE iPhone models.
Literally your entire screed is incorrect on the facts.
The ATT is the phone that WILL work least well in Europe.
LOOK at the thread title! The ATT is NOT A WOLRDLPHONE and Apple cant sell it as such . it will be selling unlocked versions of the SPRINT and VERIZON as Worldphones.