Where my eyes quickly got tired when reading on previous generation iPads, I found the Retina display helped me stay focused and interested in reading texts for much longer periods of time. Where I wasn’t too interested in reading long form articles on the iPad before (I mainly relegated that to the iPhone 4S at the kitchen table), I now consider the iPad to be a great e-book reader.
I think that overstates it a bit—the iPad 2′s screen was fine for reading—the new iPad’s screen really is better for reading. While I was never bothered reading on my original iPad’s screen, my eyes seem to relax more while reading on the Retina display, which makes reading for longer periods—an hour or so—more enjoyable.