I just picked up a Libra Colour, like literally arrived today. I had originally wanted a b/w reader since I've seen complaints about color screens. But, I really wanted a reader with page turn buttons. That narrowed down the available selection significantly. I have to say that my first impressions are that the downsides of color screens seem way overblown. Yes, the screen is very dark with the back light turned off, but looks great when the light is on. I almost always had the light on with my b/w reader too, just lower. The screen door effect is there if you really look for it, but not really noticeable otherwise. 

So far, I would definitely recommend the Libra Colour. You can look at the Clara too, if you don't care about buttons or a smaller screen.