At least they seem to have fixed that now (according to the blog post). Once they publish the fix to allow sharing the original URL, I don't see any downsides with AMP.
My issue is that it disappears whens drilling, but slides back in when I stop. I typically continue to scroll as I read, so it constantly gets in the way.
I also don't like that, but I still keep clicking links when they have the flash. Faster loading time beats usability to a certain degree for me, and most web developers are terrible when it comes to that.
I must admit, HN is probably the only more complex page I know (i.e. some interactivity, not just a blog) that loads fast on any connection.