I love my e-book reader. I own a Bookeen Cybook which is at the more expensive end of the market.
That said, most e-book readers use E-Ink technology which makes them as easy to read as a printed page. They aren't backlit, which to my mind is a good thing, and the screens don't glare in the sun.
The size of the "page" (usually about 6 inches) is good, and with some models you can increase the size of the font.
If you were to be looking for one, I would recommend the Sony models just coming out. They are not linked to one store (like Amazon Kindle) and are quite reasonably priced.