I have very little to add about the color aspect, but I can say that I love my Kobo. I've had three Kindles before buying the Kobo, which I got because it has a "better" integration with my local library (better in quotes, because I still have to do with the Adobe DRM, which is so bad on Linux that I borrow my wife's computer just to transfer). The Pocket integration is fantastic, as are the physical page turn button…
I agree the pocket integration on Kobo is the thing that sets it apart from the rest. I lost my Kobo a while back and bought a onyx boox, and although I have an almost full fledged android E-ink tablet-ish ereader now. I resent to pick it up since it's so dependent on data and electricity, I don't feel I can always just use it.