Your assuming that the item your spending more on is worth more. It's really hard to qualify on iPhone vs Android, but my super-simplified calculation is:
iPhone = 4 stars, Android = 4 stars
If the Android is $200, and the iPhone is $400, I'm gonna go with the Android
iPhone = 4 stars, Android = 4 stars
If the Android is $200, and the iPhone is $400, I'm gonna go with the Android