per TFA, ..."swapping between EVDO Rev. A, WiMAX and Wi-Fi 802.11 b/g on demand." and "The Evo 4G will swap between 3G and WiMAX for data depending on what's available"
It works just fine on the marketing networks such as 3g and 4g, and on the networks everyone else knows and loves, ev-do rev. A and wimax