Which device for iOS development?


I’m currently developing a game for Android but would like to release it for iOS too, which of course means buying something to test on. So what would be the best device to buy considering that I’m on a budget? So far I’ve come up with these three but am struggling to pick which is best:

4th gen iPod Touch, it’s nearly half the price of the other too, and has an A4 SoC which is the slowest chip I’m targeting. However it’s not getting iOS 7. Is this a problem? Or is it safe to assume that everything which works on iOS 6 will work on iOS 7 too?

iPhone 4, which has the same chip but is getting iOS 7.

5th gen iPod Touch, which has the same screen resolution as the iPhone 5. And it has an A5 SoC which IIRC is the most popular, but would not having anything with A4 make optimizing for older devices more difficult?

Thanks for any help,

Buy the oldest, cheapest device that you plan your game to run on. For example, if you want your game to run on a 3GS and upwards, then purchase a 3GS. The reason I say this is that the performance of each iPhone and iPod Touch and iPad is different. You want to be 100% sure that the game plays nicely, otherwise you’ll get down-voted on the store. Optimising a game made for a iPhone5 to run on a 3GS could be considered impossible.

The real answer, of course, is get each of the devices and test regularly. But perhaps you have friends with different devices, so you can test your game on their hardware.