If you're a T-Mobile customer due for a top-tier smartphone upgrade this October, you've got a hard decision ahead of you. Do you opt for the Amaze 4G's f/2.2 backside illuminated camera with two dedicated hardware buttons for snapshots and film? Or do you dive into the gorgeous 4.5-inch Super AMOLED Plus screen on the Galaxy S II? Both new 42Mbps devices were on hand at a T-Mobile shindig in San Francisco this evening, bathed in the carrier's trademark magenta glow, and with only the length of that gathering to evaluate these slick handsets, we'd be hard-pressed to make that decision ourselves. See some hands-on pictures of the hot new phones after the break, and our brief impressions as well!

Update: Video after the break!

Both devices' dual-core 1.5GHz Snapdragon S3 processors literally spun their respective Android homescreens in a dizzying whirl of color and loaded apps in a snap -- save the few that crashed -- and both have attractive form factors, though each feels quite different in the hand. The Galaxy S II is light as a stack of playing cards, formed of firm quality plastic that still feels a little hollow... while the Amaze 4G is a weighty, durable device with a flat glass surface encased in a metal rear shell. Interestingly, that glass surface sticks up above the edge of the frame, lending a raised surface for touchscreen typing (and admittedly a lite bit of extra girth), while the Galaxy S II has its distinctive rear chin around back and a slightly finer textured surface than its exceptionally close cousin the Epic 4G Touch. Trade-offs. We're afraid we didn't get to test the 42Mbps HSPA+ speeds in San Francisco, but we did get to see the Amaze 4G's camera in action -- and in the low light here, it was fairly true to its name. Pictures and video below!