I played with a Kobo glo and was impressed with the lighted scree. The illumination was very even, no discoloration or shadows or anything light that. The source of the light along the top was very discrete and not noticeable. I will say that I only used it in lighted store conditions. Overall, I was very impressed. It was slightly blue, but that didn't bother me.
It certainly looked a lot better than some of the images I've seen of Paperwhites, but I have never handled a Paperwhite so I can't judge. Also the Kobo (and the PW) handles pdfs poorly, so that's a show-stopper for me. Also I understand the Glo screen (like the Nook) is fragile so I wouldn't buy one.
However, the good news is that the front-lit tech is looking practicable but I will be waiting until the various issues are ironed-out. Overall, I'd like to see a Sony with a lighted screen as good as the Kobo. That way I'll get the best of all worlds. I would consider a Nook is they make the screen less fragile as I can root it and have the software flexibility I want.