The software that they develop on for iOS is supposed to be top notch, which kinda helps and they only have to test that their app works on a handful of iOS gadgets, whereas with android there are thousands. Also, with the Play store (apparently) when you specify which devices your app works with, you have to exclude devices one by one manually, rather than just put in a list of stuff you've tested that it works with. You could, of course, just shove up your app and let users work it out, but then you'll get shitloads of one star reviews...