I've recently bought Hisense hibreak phone just because I am interested in these things.
I used both as a cycling computers, without sim and almost without internet.
It is fine, not great yet, but not bad. Just a bit on a slow side. But overall it is a working solution for my goals.
Screen seems to be worse for maps then I remember screen from hisense a5cc phone. Maybe it is just my memory, though.
Same with battery: it.seems.to be a bit worse then in A5 CC.
Overall, I think color eInk technology is not there yet, at least
I've recently bought Hisense hibreak phone just because I am interested in these things.