I wouldnt get an ipad for ereader purposes. Since it uses a normal LCD, it is going to have the same readability problems associated with any PC/laptop, mainly increased eye strain. Simply put it is more of a strain on your eyes to look at a backlit screen like that for long periods of time than a screen like the kindle/nook, which has much more of a paper look.
Plus I would rather chop off my hand than give any money to apple.