There are other forums like Turk or Howard Forums that are more geared to your question. That said, the CDMA (Verizon) BYOP is a bit more iffy than the GSM BYOP, which is far more open. There have been reports of lots of Verizon branded phones being activated on CDMA, but there have also been failures. The reason for the failure has not always been clear. On the GSM side, as long as the phone is AT&T branded or is "unlocked", it will work. On the GSM side, the sim is activated, the phone make/model is never identified to TF. The only issue on GSM could be getting the right APN settings to get Data and MMS working correctly.