Thanks to Netgalley and Dark Horse Comics, I've been able to read a few graphic novels on my awesome Nook Color. So far, I've read the first two volumes of Buffy The Vampire Slayer season 8, and Star Wars: Knight Errant volume 1.
It's a much different experience reading them on the Nook Color instead of the dead-tree versions. When I hold a graphic novel in my hands, I'm careful not to crease the spine and gentle when turning pages so I don't tear them or rip them off the spine. No need to do that with the ebooks.
However, I'm too lazy to zoom in on the individual panels in the comics. There were just a few times I had to squint to make out some of the text in busy speech-bubbles, but most of the time I could easily make out the text.
Dark Horse always has great artwork in their comics. The ebook versions, when displayed on the Nook Color, take that great artwork and make it almost cinematic. The color touchscreen, basically a small computer monitor, really pushes the colors off the screen. They're so vibrant it seems more a paused HD movie screen-cap than something an artist inked or painted. To me, that says the artwork in these comics is just as good, if not better, than movie-quality.
If you have a Nook Color and enjoy graphic novels, I'd definitely suggest trying out the ebook versions. It's definitely a visually pleasing experience.