While the iPhone visual requirements make their product more streamlined, this does enforce very limited amounts of creativity regarding your product image. Android, on the other hand, allows for extended creativity and a more varying image in the market.
From my understanding the programming languages are also similar in comparison. iOS seems to be made more for the use of people who are more experienced in graphical design and display, whereas Android allows for much greater flexibility within the code and seems to be directed more towards programmers.
Suffice it to say, I’m finishing up the adjustments needed to the iPhone/iPod Touch Curvy icon image requirements. It always amazes me just how much detail there is regarding some aspects of image creation.