I do like 6 inch e-readers, I think I would have to see IRL how the screen looks. For my usage color is not necessary, I don't even read manga on my device because I haven't found a good reader. I had bought an android based one for this purpose but I didn't like how the screen looked. I guess I'm fairly picky. I think the only reason I'd get a colour one is simply to see book covers in color. It's minor but it might…
I wouldn't mind an even smaller screen. I read fiction on my phone in bed to fall asleep at night. In order to do that, I have to lay on my stomach and hold the phone with one hand. I've tried it with my 6" Kobo Clara 2E and it's just a little too awkward to be usable. Maybe if it had some physical buttons on it somewhere, but it doesn't.
Why? I mostly lie on a side when reading and prop the reader (or the paper book) with the bed sheets.
This has the potential to turn into a reading positions subthread :)