Giggs: My only bugbear is the fragmented nature of Android updates from manufacturers since they generally all seem to want to add their own features to any new Android version before they roll it out, whereas with Apple one size fits all.
The thing here is: does it matter? There are some bug fixes that make it into updated Android versions, but most of the changes are new (optional) features. Unless a particular app needs those new features, there isn't usually any real need to have the phone's OS updated.
The only thing that breaks this pattern are the app layout changes introduced in Android 4.0 (ICS / Ice Cream Sandwich). These changes make it easier to have an app support different screen resolutions. However, I believe that app developers can include both the old and new layout schemes in an app, which helps to make this less of an issue.