What is the best way to clean it? And with what?
I bought a 2015 rMBP when they first came out. I've heard about the peeling issues on the screen just never looked much into it. On my old 2007 MacBook I'd use anything to clean the screen, windex, water, etc...
A bit of water on a microfiber cloth. Do NOT use any "window cleaner" - they have chemicals that will destroy the coating on the screen.
For dust I usually have a dust blower close by that I use for my cameras and lenses, and I've been using that lately for the screen.