The Samsung Craft is the first handset made specifically for LTE 4G speeds, and MetroPCS--which was also ahead in rolling out an LTE market--is its first taker.
Unfortunately, at the time of review, 4G is only available in Las Vegas and Dallas/Fort Worth. Since there's only limited 3G network nationwide, most people will fall back to the 2.5G network until their area gets MetroPCS 4G coverage.