Everyone has their own opinion and that's fine, but saying Android is more efficient than iOS just is demonstrably untrue that I'm not entirely convinced you typed that with a straight face. There's also only one phone that has a camera as good as the iPhone, and that's the newly released Pixel. Every other camera falls short in independent testing.
About the camera: That's what I thought as well. So I presented my phone proudly in a bar to friends, all of them having Android. We shot some photos, and each and every photo was better than on the 6S. 100% and live.
About the efficiency: Agreed that it's a hard thing to argue. But the reason is less that it's not measureable, but because it's hard to convince people of efficiency that they don't even deem possible. Best example for me is Vim vs a random simple text editor. People who use the latter are hard to convince of why Vim is way more efficient, since they can't even imagine what you can do with Vim. In the same regard I know few, really few people, who even try to achieve some level of efficiency on their phones. But in fact since I have paid for the iPhone now I would love to be convinced from the opposite myself. So if you have some neat efficiency tricks (e.g. how to get a typing speed of not lifting your finger at all + good word guessing on an iPhone) I'm happy to admit being wrong.
