I recently updated the solid state drive in my Acer C720 Chromebook to this 128 GB drive following these directions. It was easy – nothing to fear, here! Now we no longer have to live in the cloud and this very inexpensive but powerful little laptop becomes a ful-fledged computer. Next install chrx paying careful attention to the notes specific for your model Chromebook. Then, I highly recommend the Gallium OS. This is the most beautiful Linux version I have ever tried. The installation was a breeze and it works much better on my Chromebook than my previous setup using Crouton and Ubuntu. Excellent installation instructions for Gallium OS are here. Be sure to check the hardware compatibility list first.
And in case you miss this detail: When booting up the Chromebook, at the Developer Mode screen hit Ctrl-D to boot in Chrome OS or Ctrl-L to boot in Gallium OS. DO NOT HIT THE SPACEBAR unless you want to start all over again!