The extra resolution makes a big difference.
I had a Nook Touch (gave it to my son so I can still look at it for comparison).
I red on it at the (highest - 2) font size as my eyes are getting older (only my eyes!) with the result that not a lot of text did fit on one screen.
Now I got the Glo, I can read with a much smaller font. I believe this is due to the resolution.
Also, on the Nook the font sizes went up or down in pretty big steps so either the font was so small that I had to read with my arms straight or it was so big that I turned the page every second or two.
The Glo is a lot more adjustable.
I would have stayed with the Nook Touch but for the light feature. I read in bed and the light is great. I could have bought the Nook Glow but the extra resolution and the extra adjustments made the Glo a better proposition for me.
I considered the Kindle PW but as it is not available here yet and as it does not support EPUB I got the Glo.
Now that I've had it for 4 days I am happy with my choice even though it froze on me 3-4 times while I was playing with the margins adjustment (I have now confirmed that the freeze is specific to one EPUB I have).