Hello, I am trying to understand which phones will communicate at 4G speeds with t-mobile. I called T-Mobile. My rep says an AT&T EVO phone will only communicate at EDGE speeds because of the internal antenna??? I understand that only a 4G capable phone will communicate at 4G speeds, what I want to understand is which phones on Ebay or Craigslist will work on t-mobile at 4G speeds. Another friend says I can only buy a phone that has the t-moblie emblem to get 4G speeds??? Is there truly a different antenna inside the phone to communicate at different bandwidths? Also I would like to understand unlocking vs jailbreak vs rooting? Thanks you to anyone who is willing to help me as I move into the android market.