If you've got a Chromebook or Chromebox, your next update could be pretty awesome. ChromeOS is getting the material design treatment and the result is fantastic. It is a nice fresh taste that was long overdue. ChromeOS, while very funcitonal, looked like something out of the Windows XP era. This brings it into the Windows 10 era and it looks great. It seems to run really well and look even better on my 1080p Tegra K1 Acer Chromebook.
Once you're moved over to the beta, you can submit feedback by hitting Alt + Shift + i. And, if you happen to experience bugs with the beta, you can revert back to the stable version pretty easily - but the caveat is that it will delete all local data, so you'd want to make sure that all of what you need is backed up, or stored in the cloud.