The app would ask you that it wants a specific permission, and you can choose Y/N.
Let's say a flashlight app. It will ask permission to use your camera (for the flash function).
If it asks to access your contacts or billing info, you can know it's shady and disallow it.
Android however, will only show you list of permissions used by the app.
And that's it... You will get hekt
iOS is a bitch when it comes to getting your app on the App Store.
Android well... it's friendlier to developers. They can test their apps easily.
WHICH IS GUD 4 HAKERZ