I wrote a bit a while back on Reddit regarding my experience with the C201 and Linux: https://www.reddit.com/r/linux/comments/bebm93/linux_on_asus...
Now with open 3D acceleration, the last remaining bit of proprietary code on the C201 is the WiFi chip. Not sure how much of an impact it'll have, but when Cypress bought Broadcom's wireless division it released the datasheet for this and many other chips (PDF): https://www.cypress.com/file/298141/download
Alyssa Rosenzweig is making amazing progress with Panfrost working at Collabora. Panfrost is now working with GNOME, two months ahead of schedule!: https://rosenzweig.io/blog/gnome-meets-panfrost.html