T-Mobile is playing up the idea that the myTouch will be more customizable than the iPhone, via skins, widgets, and other interface tweaks. I haven’t seen any of these features, but they sound like a logical enough to the question “So remind me again why I should buy this instead of an iPhone?” Which is a query which every non-Apple smartphone must answer explicitly or implicitly. Palm’s Pre does so in part through having a strikingly different form factor than the iPhone; the myTouch looks a bit like a chunkier iPhone (it has a removable battery) with a smaller screen and more buttons and a trackball.

Like TechCrunch’s M.G. Siegler, I’ve been playing with a phone that’s essentially identical to the myTouch from a hardware standpoint–the Google Ion, which Google distributed at its I/O developer conference last month. It’s a pleasing phone that looks good and fits well in the hand–one of HTC’s nicest industrial designs. I still think that Android is a promising platform that’s still in search of major unique benefits to consumers, but perhaps T-Mobile’s customization options will help. In any event, it’s good to see a second Android device come out, even though the OS will only live up to its potential once there are lots of Android phones.

The myTouch will sell for $199 with a two-year T-Mobile contract; that’s the same price as the Pre and the 16GB iPhone 3G S.

Here’s a quick photo of the iPhone 3G S and the Ion–the Ion is black, but the myTouch will come in black, white, or “Merlot.”