I think crouton is a much better-integrated experience than dual booting. You can set up the Ubuntu chroot exactly the same way you have in this, but you don't

I think crouton is a much better-integrated experience than dual booting. You can set up the Ubuntu chroot exactly the same way you have in this, but you don't have to reboot if you want to watch Netflix or use Chrome OS. With the crouton integration extension (synchronized clipboard, open links from Ubuntu in Chrome OS), Chrome OS will feel like "just another app" (even though Ubuntu is the "app"/chroot). Another benefit of using crouton (with an SD card) is that if the user accidentally hits space during the boot warning and developer mode is disabled, they can simply re-enable developer mode and nothing is lost in the Ubuntu chroot. Unfortunately, the C720 has an extremely slow SD reader, so you'd probably want to go with the Dell Chromebook 11 (same processor, ~90MB/s SD reader, better battery and build quality, $70 more) if you wanted to go this route.