Android > Iphone
1. Multimedia data transfer is easier (Iphone uses sync which is limited to a single pc and the needs for itunes)
2. Flash playable browser
3. Swype input is simply the best invention for touch screen phones
4. Customizable dynamic UI

Iphone > Android
1. More games, and apps support
2. Better scroll and pan control response
3. Stable and easy to use for mediocre user
4. Accessories availabilities