The processor is one of the only thing Apple has a clear lead in over Android flagships. (Others being customer support and longevity)
Android hardware and software are fully stable now. Android phones have better cameras and match apple in most other hardware metrics (display, speakers, antennas, build, touch response)
Software wise, it comes down to preferences. Both have a few things they do well, and others they stumble on. iOS12 is from what I have heard, smoother as butter. However, top flagships from Samsung, Google, OnePlus all run Android without any stutter at stable 60fps too.
All of my daily apps/usecases are at parity with their iOS. I don't know if the app ecosystem complaints are valid in 2018. (Apart from snap chat, because they have some wierd hate for Android)
I can respect your choice of wanting an Apple device. Especially if you are invested in their hardware and software ecosystem. But to someone who isn't, the iPhone does offer enough to switch from Android.