[luag]

Are we talking about american comics or japanese mangas?

American comics, which are usually colorful, don't look so great on greyscale screen.

The usually BW japanese mangas are a little better, although i personally think that 6" screen is not big enough. It's readable, but not optimal.

Edit: Unless you resize the files. If the image is bigger than the screen, the downscaled images are not smooth, and it makes texts hard to read. So you have to zoom the images at 100% and you have to scroll left/right, up/down.