Not too long ago (summer 2017) Asus graced us with their second Chromebook device that sports a 360 degree hinge, called the Asus C302CA Chromebook Flip (Asus C302 for short).
Months before it was available for purchase, I was lucky enough to get my hands on one for about 20 minutes, and wrote about it here: https://www.chromestory.com/2016/12/asus-flip-2-review/
That model had the M3 and scored about a 22000 on the octane test. The models that started shipping right away had Pentiums and shortly after the M3s were available.
Fast forward to today, and Asus now has an M5 (m5-6Y54) option for US buyers on Amazon.
I don’t know anybody that has one yet who can report on the performance, but if I were you, I’d keep an eye on Chrome Unboxed and see if they don’t get their hands on one and give us the skinny.