The T-Mobile G1’s hardware design will be familiar to users of HTC’s Windows Mobile handsets, a lineup that includes the AT&T/Cingular 8525 and T-Mobile’s own Wing, both of which I reviewed for InfoWorld and continue to use (see “Smartphones for extreme mobility”). This mature design, with fashionably subtle tactile buttons underneath the display, incorporates a touch screen that’s sensitive to both fingertip and stylus, as well as a slide out full QWERTY keyboard. (In T-Mobile G1’s case, the keyboard swivels out in a half-moon motion while remaining parallel to the display.) That’s right, it’s got actual keys that don’t take up any space on the screen, and the keyboard disappears when you don’t need it. When you flip out the keyboard, the display rotates from portrait to landscape view — again, mimicking the behavior of HTC’s Windows Mobile line.