I will recommend you buy the cell phone in USA. In Taiwan tri-band phone is often 800, 1800, 1900 frequencies. In USA it is 850 and 1900. You can "get by" with 1900 but outside of Boston the 850 frequency is really helpful. You should get a phone that supports both 850 and 1900 frequencies. Those are pretty much only available in USA.

 

Also, "usually" AT&T and Verizon has better reception than T-mobile, but only T-mobile offers 1 year contract; the others are for 2 years. T-mobile has no 3G service.

不會啊~台灣的三頻機也有很便宜的，二三千元就有呀!