I got a Kobo about a year ago (Libra Color) it is just great. The kobo store keeps having sales on books I want for $2 so as much as I intended to use the overdrive connectivity, I just keep buying books on it!

Have you considered trying to repair it? Darkened screen sounds like failed LED lighting strips and those can be replaced. Watch a few videos on the subject to get an idea of what you are getting into. I did it on a vizio TV and it took me about an hour all told.