From the point of view of a developer, one counter-point is that the App Store still makes far more revenue than the Android Marketplace (about 17x more, to be precise), so iOS is still a better platform of choice [1].
A counter-point to that counter-point is that Android's Marketplace has far fewer apps than the App Store (about 4x fewer), and far fewer paid apps (about 2x fewer) [2].
That 8x factor still doesn't explain the 17x difference in revenue. My guess is that the typical Android app is of lower quality (since the store is not moderated) and lower priced in comparison to iPhone apps.
At any rate, given this dramatic change in market share, it seems to me that not deploying for the Android platform at this point is a dangerous proposition, except perhaps if your primary customer acquisition channel is the platform's built-in store/marketplace.
[1] http://techcrunch.com/2011/02/21/861-5-percent-growth-androi...