How's reading PDF textbooks on an e-reader for you? Personally, I've found them a nuisance because you are not able to skim through pages quickly as you can with a traditional textbook. Let's not forget the small screen size.
Yeah, it's massive drawback. I prefer it anyway as it incentivises better features (at least I want it to): I can envision a reader that shows the edges of the pages so you can flip through many at a time (ie think of how the pages don't line up when the book is opened flat). I use the Microsoft Reader so I can use the pen so probably no such luck for me.
Also advantage of the ipad is you can load it up more modern that can assist your learning where by a book is a dead tree.