Because the Nexus S comes unlocked even with a T-Mobile subsidy, it's a great choice for world travelers who might want to pop in a SIM card from whatever country they're visiting. But in the United States, your options are the same with the Nexus S as they were with the Nexus One: 3G coverage from T-Mobile and 2G coverage from AT&T. The phone lacks the proper antennas for any other carriers or for AT&T's 3G network. This was no secret, but it's worth a reminder because the Nexus S Website doesn't make it clear.