Link here. Essentially, the phone will often be stolen, and will inevitably be blocked, leaving you with a brick.
Posted from the airport in Madrid, awaiting my flight to Israel. I am also sitting here enjoying some fantastic European airport fast food, far better than one sees in the U.S. Lox and anchovies with cream cheese on a wonderful piece of flatbread. I had a similar experience flying through Italy a few years ago. In this area the Europeans have Americans beat.