Everything has been great. Best phone experience I've ever had.
T-Mobile doesn't sell the Dev Edition. You can see T-Mo's version HERE. As far as I know you can only get the Dev/64 Gigs version straight from HTC HERE. I didn't see it on their site so they may have sold out (it's limited edition). HTC is also offering up to $300.00 rebate on the One if you buy one now.
Right, but my question is about the data connection. Are you able to get 4G LTE and 4G on T-mobile's network with your phone? I heard that the unlocked version from HTC does not support as many data bands as the HTC One version from T-Mobile, so I figured The T-Mobile version would be the better version to get.