I used my new IPhone 6 with Tmo in France, Italy (more Tre than TIM), Switzerland and Belgium. It was a bit erratic, with Facetime working incredibly well but some sites very slow to load (and draining the battery a bit). All in all a very happy camper relative to my days with AT&T and their expensive data that did not seem much faster in the same locales. On occasion my Italian SIM (Vodaphone) was significantly faster on my other phone.