Important: Please read this comment before deciding to opt-in and enable the NXOE on your console:
Certain games and apps will not work/load in the NXOE Preview. Some are big name popular games (Forza and Destiny TTK are on this list). This is going to upset some people, and they'll likely want to exit the NXOE Preview to resolve that issue. If you do that, your console will be FACTORY RESET - meaning all games/apps on your hard drive, accounts, files, etc will be wiped from the internal HD.
It's a beta program - things will go wrong.