In general, prepaid phone users can purchase any kind of unlocked GSM smartphones to access plans offered by either T-Mobile or AT&T. But there are many things to consider, such as frequency bands and other details that may confuse them.
Earlier Google’s devices can work well on both carriers, but it’s different with the HTC One Google Edition, since Google was not involved in the design process to ensure better compatibility.
That means, prepaid phone users planning to purchase the HTC One Google Edition will get reduced data transfer speed in areas where the carrier’s 4G network isn’t available. The Google Edition on HTC One isn’t compatible with HSPA+AWS services offered by T-Mobile since it lacks the necessary support for frequency bands.
It appears that the phone can’t access T-Mobile’s 2100MHz HSPA+ band. To fully access the HSPA+AWS service, a phone must support the 1700MHz and 2100MHz bands. On the other words, with HTC One Google Edition, prepaid phone users will not receive the usual 21Mbps to 42Mbps HSPA+ speeds on parts of T-Mobile’s coverage area.