Hello, Sprint agreed to let me out of my contract since the coverage in my area is kind of bad, yet they claim it is fully "built-out." I have the Sprint iPhone 5S and I am considering going to T-Mobile with it. I did this one time before, but it was with a Verizon iPhone 5 going to T-Mobile, and the iPhone 5 did not have the T-Mobile LTE bands in it, and I was always on either "4G" or "E" despite living in an LTE area. The Sprint iPhone 5S has every band in it, so I am figuring that I can just put a T-Mobile SIM card in it, and it should work just like a T-Mobile iPhone. My questions are: 1.) Will this work? 2.) Does Sprint need to unlock the phone first? 3.) Will I experience sub-par service as compared to someone with a T-Mobile iPhone 5S? 4.) A friend of mine said he used to have an Android phone and got excellent service in a certain area. He now has a 5s like me, and also has bad service. Is it possible that an Android phone and an iPhone could have different service on the same provider in the same area? Thanks.