Huawei Ascend D. D1 for lower price or D quad for bigger battery. Most high end GSM phones in China have quad GSM band, meaning you can use phone function worldwide. In addition, Huawei Ascend has five-band WCDMA, meaning you can use both ATT and TMobile 3G. Make sure it has five-band WCDMA (especially 1700M) if you plan to use TMobile 3G.