I'd say the contrast is similar to newsprint.
Sometimes I wish the startup was faster, as when I want to make a quick note. I use mine as a notebook a lot, and I try to remember to turn it on a while before I'm going to need it. When I was at a conference last fall, I kept it on all day, and even with heavy use of the Wacom pen input, the batteries lasted 8+ hours each day.
I also kind of wish it had onboard HWR, at least to index and search my notes.
Maybe someday.