"Like the iPhone, the Google phone's best feature is its attractive, well-designed interface. The most important thing about the G1 is not what it does but how it does it. This sounds obvious: Doesn't every mobile phone company set out to create a usable interface? Spend a minute trying to navigate deep lists of drop-down menus on a Windows Mobile or BlackBerry device and you'll have your answer. Before the iPhone, phones were pretty to look at but a pain to use; the last blockbuster mobile phone, Motorola's RAZR, induced aneurysms when you tried to do anything but make a phone call."
Read the whole article at Second Bite at the Apple: What the Google phone stole from the iPhone.