Which smartphone operating system do you think had the biggest gain in the most recent Nielsen ratings? I'll tell you who. Android. Despite having a couple year head start the iPhone and iOS combination is giving up ground to the more open Android ecosystem. Now the lead stands at just 9 percentage points.
Nielsen has pegged the Android OS as the single fastest-growing mobile platform. Apple's iOS has declined very slightly despite the release of the iPhone 4. This my friends is probably the reason that Apple has finally decided to "play nice" and allow the iPhone on multiple carriers. It's come down to open and compete or die.
Jolie O'Dell at Mashable has a great write-up on this and a few other eye-popping statistics so I suggest you check out her full article here: iPhone Versus Android: Nielsen Delivers the Numbers [STATS]