The color screen of e-readers is too dark for me and substantially lacks contrast. It's very noticable. The layer for pen recognition already makes the screen darker, but the color display is adding a lot more to the darkness and lack of contrast.

There were a handful of reasons I returned mine, but this was the biggest one. Color eink isn't ready yet, and the limited color palette wasn't even the worst part... it was the dark screen. Needing to use the backlight so often is just disappointing, and turning it on negates all the good stuff about eink, making you feel like you're using a really shitty tablet. Maybe things will be better in a generation or two, but if you need color you might as well get a conventional tablet.