Hi – not sure if you want comments about the Alpha version here or not but here goes.
I’ve just set it up on a test site and so far so good. However looks like there is an issue with mobile menu when using the official AMP plugin (with AMP for GeneratePress active as well).
Basically hamburger works fine without AMP but when you have AMP active with the GP plugin, the hamburger disappears altogether so no way of seeing/accessing primary menu.
If it helps, they are the only two plugins I have active and I have no custom CSS/PHP.