i've never really had a problem holding the jetbook. i think it's fairly light and easy to hold - which i definitely like. i usually read in bed while on my stomach so i usually have the jetbook either up against my bedboard or flat against the bed.
the best way to read is definitely while laying down on your back with the jetbook in the air. its so light that it really can be achieved with no problem or strain after a long period of time.