Hello, so as the title says, I have an AT&T iPhone 6. If I wanted to leave AT&T and go to Verizon can I? What about T-Mobile? Also, would they be fully compatible? Like have LTE, not just HPSA+. Thanks for all responses guys! I'm either going to join my family on Verizon or go on my own if T-Mobile unlimited. Paying AT&T $65 a month for 1GB isn't going to cut it haha