In bold above is the reason for me.-If you have an old phone, it's the same thing with Apple. You can't upgrade older versions and miss some features from the new releases. If the phone is two years old or more or you own an iPod touch. If your phone is a year old or the current shipping device then you're pretty much guaranteed two generations worth of updates as and when released. Not so with android. Recently shipped phones have to wait weeks or months which is what irks me. Some even ship with older OS versions on purpose. Ask if they're planning to release the latest update for it soon and you get 'we're still considering"
Android uses the same-ole same-ole model when it comes to updates. Google will code it, but you're totally at the mercy of whoever made your phone, and then your carrier, as to if they'll ever port/release that update for your specific device.
With an iPhone, I know I get at least two solid-years of free OS updates.