Based on my experience with the iPhone OS, you don't really have to check for any of that unless you want to use that particular feature. For the vast majority

Based on my experience with the iPhone OS, you don't really have to check for any of that unless you want to use that particular feature. For the vast majority of simpler apps, all of that is transparent. If CPU speed is an issue (games, mainly), it does help to have a pre-3GS around to serve as a baseline, but I think that the process is much less daunting than you try to make it seem in trying to play down the uncertainties of dealing with Android's fractured ecosystem.