Now that my METV has been approved, is this what I bring with me to the airport and customs/immigration as far as the visa is concerned? Do I save this .pdf they emailed me and print it out? There is a QR code on it, I assume they will use that QR code? Or is there something else that I should print out or show proof for visa?
TLDR : Answer Summary
You should bring the PDF of your approved METV to the airport, print it out, and keep a copy with your passport. This document contains a QR code that will be scanned by immigration. It is advisable to save multiple copies and check your passport for the correct visa stamp upon entry into Thailand. Other users have successfully showed only the email version of their visa upon arrival, so having digital copies is also useful.