[Alan_S]

From what I read (never had one) KA1 has these main problems from my perspective:

-capacitive touch display which influences look of display (another layer between eyes and screen), but also some people find it very scetchy. It may depend on actual device, I don't know.

-flush bezel, I don't like it, it makes screen much more prone to scratches, problems with cover, all in all, you have device that have certain problems because screen is on same level with rest of the reader front surface.

-screen illumination, and I don't mean the one that don't function right because some factory error. I see there's a lot problems reported with how algorithm works. OK, that is nickel related, koreader at the moment doesn't support light temperatures (or I don't know something). Also, it looks it needs to have lights on all the time and it prefers higher light setting when there's more light in ambient. Of course, all of that can be solved by manually controlling lights.

-battery is much smaller. It doesn't need to be a problem. From my H2O I get about 10-14 days of reading, so I guess I would get 3-7 days with KA1.

All in all, I also very much prefer bigger screen than H2O, but if I would need to buy new device, I'd still try to buy H2O at the moment (first gen, not second). If I can't, I'll try KA1 and hope I don't have too much problems with device (you see a lot of faulty device reports, but this is just that, possibility with every device).