this is interesting comparison of OS versions runing on Android and iOS and ‘developer friendly environments’ from the SDK perspective:
“The number of devices per OS is a great marketing number for Google and Apple to fight over but as a developer—who wants to get the most out of the SDK—I care about the version of the OS on the devices. If I want to use the latest and greatest SDK’s I’ll take Apple’s 80% of 21% over Google’s 30% of 28%.”
http://jeffreysambells.com/posts/2010/05/20/android-vs-iphone-development-decisions
“The iPhone has another big advantage and it solves the problem of distribution as I alluded to earlier. iPhone users use iTunes to sync their devices and add content. The process of syncing the device also checks for updates and allows all iPhone OS devices (iPhones, iPod Touches, iPads) to download the latests version of the OS. As a result the March 2010 iPhone Platform Versions stats look very developer friendly”
“More than 50% of the Android install base is still using version 1.6 or less. As a developer what should I do? If I choose to take advantage of the latest and greatest SDK I get less than half of the devices! But still, the bigger problem is there is no clear and easy upgrade path for those bottom 50% to get the newer OS version”
∫ ∪ ∧∴ ∋ ∈ ⊇ ∧ 
Currently, maybe even more important is the Android hardware fragmentation. iPhones are using similar displays (just two resolutions), similar cameras, etc.
However, this could significantly change over time. There is new iPad and iPhone on the way, users are still using old iPhones… And we have numbers of devices with at least 4 resolutions in 2 sizes, different graphics and CPU (OpenGL ES 2+ devices and older), different gyros… Maybe it will be similar mess ;-) At least for graphical application development (read games and other 3D OpenGL apps).
I agree, however the way how iPad handles the smaller resolution of ‘legacy iPhone apps’ by magnifying it 2x is very elegant. Apple does very coherent appliances, others do (varying)HW+(varying)SW.
I like what Larry Ellison said here : http://www.reuters.com/article/idUSN0740285120090507 :
“While most hardware businesses are low-margin,
companies like Apple and Cisco enjoy very high-margins because
they do a good job of designing their hardware and software to
work together. If a company designs both hardware and software,
it can build much better systems than if they only design the
software. That’s why Apple’s iPhone is so much better than
Microsoft phones.”
That said, Apple has always ‘full control’ otheres don’t, they have just rules and policies. Windows Phone 7 can get best of both worlds and with Microsoft ability to abstract HW and update OS, integrated dev env., cloud-mobile continuum, this could be in a long term appealing for both consumers and developers.