I recently purchased a 64GB WiFi + Cellular iPad Air 2 (Gold). And it should be here in a couple of days. I am going to travel quite a bit with it from Georgia to Florida to Oklahoma (all around the South.) For you guys experience with it and the best bang for my buck, which Cellular LTE network should I go with? I have heard that AT&T locks the SIM in if you choose it? Is that true? I wouldn't mind that as long as AT&T is the best network... But I'm not too sure which one is the best for me. Any ideas? Is it still just a 30-day plan (that you can choose when to put it on) and not like an all year-contract plan? Thanks and I would appreciate any help. As you can tell my 1st Gen. iPad is too old and slow for me nowadays.