As a user, I've found AMP results to be invariable an excellent user experience on mobile. I will always click an AMP link over a non-AMP link, when on mobile, because I know the AMP link will load quickly and be usable, and the odds are good the non-AMP link will not. Apparently this is a minority view around here. :)
1. Scrolling momentum is very different, making it feel non-native
2. The URL bar doesn't hide normally. Scroll down in portrait mode and it doesn't hide.
3. The URL bar doesn't un-hide normally. Switch to landscape mode and scroll up, the URL bar does not reveal itself.
4. Safari Reader mode often doesn't work.
5. Scrolling before the page is done loading can make it look like there's less content then there actually is.
6. Some dynamic sites misbehave (e.g. reddit does not show me as logged in).
7. Copying the URL results in some Google thing instead of the real URL
8. Relationship between AMP X close button and Back button is confusing
I am curious which of these you experience, which you don't notice, and which you don't experience at all if you are an Android user?