For what it's worth, versions newer than android 2.2 do have features that are worth using. My personal favorite is hardware accelerated graphics. That really does make the phone's UI feel as snappy as the one on iOS.
Then there's the support for multi-core apps (introduced in 3.0), resizable widgets (3.1), social API (4.0), calendar api (4.0), beam (4.0), low-level media streaming (4.0), media effects(4.0) .. and many many others. Android 4.0 is full of goodies.
My first Android "app" (actually, a runtime for HTML5 apps call Blossom[1]) only will run on ICS because its requires hardware-accelerated graphics and surfaces.
On iOS, I could support all the way back to the original iPhone, but I'm actually requiring iOS 5 (that includes all three iPad generations, and the iPhone 3GS, 4, and 4S) mainly so I can use ARC and because people in the iOS ecosystem update so fast anyway.
