It's only been six months since Samsung launched its highly successful Galaxy S assault upon the US market with a series of carrier customized phones: the Vibrant and Captivate GSM twins for T-Mobile and AT&T, the WiMAX-rocking Epic 4G for Sprint and the Fascinate for Verizon. More derivatives arrived later, with the Mesmerize, Continuum, Nexus S, and LTE-equipped Galaxy Indulge. Still the Vibrant was the first, and the closest in appearance to the original Galaxy S, losing the front-facing camera, but gaining a search button. Unfortunately, Samsung was slow to upgrade early devices like the Vibrant beyond Eclair, and to fix the well-documented AGPS problems. As such, the release of the Samsung Galaxy S 4G for T-Mobile -- basically an updated Vibrant with HSPA+, a front-facing camera, a bronze battery cover, Froyo out of the gate, but no dedicated internal flash storage -- is bittersweet. While beneficial to those who waited, it's a slap in the face to those who purchased the Vibrant. But is it a worthy upgrade? How does it fit into T-Mobile's high-end Android lineup? Read on for our full review after the break....