We have Tmobile and used it last year in France, Belgium, and the Netherlands. It was quite spotty and hard or impossible to get a good data connection at times while on the go. I had not opted for the International pass and so probably got a slower connection at times. I use it quite a bit for Google directions and such on our Iphones.
Have any of you had a good experience with the Tmobile International pass in Italy? I imagine in larger cities like Florence or Rome there would be few problems. Not sure about places like Sorrento, Capri, Pompeii.