I run a 10-person development team, split 50:50 Android / iOS, under a digital agency. We build apps for carriers (account management apps), brands, etc.

From my own personal experience, which having built apps since the first iOS SDK and Android 1.6 is hopefully fairly reliable, the QA and testing burden on Android apps is considerably higher than iOS.

That in itself isn't totally surprising, because there are far more handsets on the market. But that's not the real issue: say I'm writing an app for a network carrier. Carriers typically want their apps to run on all hardware they've sold for the past two years (ie, everyone who's still under contract).

On iOS, that's iOS 3-5. Very soon, it'll be iOS 4-5 - 4 was released in June 2010.

On Android, that's 1.6, 2.0, 2.2, 2.3, 3.0, and 4.0. Because the key difference is when Apple release a new version of iOS, they stop selling the old one. But that's not the case with Android. Even today there are still phones on the market running 2.1.

When you say "the same fragmentation exists on iPhone but smaller in quantities" - I don't really think you know what you're talking about. If you're developing an app now you can pretty easily support iOS 4.3 upwards, which would cover all handsets being actively sold by Apple for the past 21 months or so (the 3GS onwards, or three phone models and two tablets)). How many Android phones running how many versions have been released in the past 21 months? Far, far more.

This doesn't inherently make Android a bad platform: lots of people choose to develop PC games even though there's a much higher testing burden that consoles (in terms of the varying environments and OS versions). I think Android is great: I'm not arguing against developing for it. But I think you'd be very hard pressed to find someone experienced with both the iOS and Android platforms who'd disagree with the notion that fragmentation on Android takes up a lot more time to deal with than iOS.

Apple's major versions come out once a year, while Android's about twice per year. In this case Android 2.1 (early 2010) is even newer than iOS 3.0. Are you saying nobody has an iOS 3.0 iPhone anymore?

I don't think phasing out versions is a big deal for Android. It happens about as fast as for iOS (~3 years). What is a bigger deal is how fast the latest OS/API gets adopted. iOS can push out the new version in days to at least 50%-75% of the users, while for Android it takes about a year to be on 75% of the devices (that's how long it took for Gingerbread).

And the issue with that is that users don't get to take advantage too much of the most cutting edge software, until months after release, when (or if) they get their upgrade, while on iOS they can do that just days later.

The degree of variation in iOS is nothing like what you find on Android.