Was with T-Mobile for ten years, five of them with an unlocked 2007 iPhone.
When T-Mobile didn't get the iPhone 5 last year, I decided to switch to Verizon.
Make a long story short, I sold the VZW iPhone 5 and went back to T-Mobile when they officially got the iPhone this past spring. Despite some good reviews, I was surprised that VZW's sound quality was "tinny" sounding. The only think I don't like about T-Mobile is that reception is great in city and suburban areas and along interstate highways. Not good in rural areas away from state or Interstate hightways. Otherwise, a great deal.