It's a tough call. If we go for feel alone I prefer real books, I love turning the pages, I love how books smell, I love having a bookshelf full of books and going to second hand bookstores. That's got a lot to do with how I was raised though.
But iBooks have a lot of advantages: I can get a new book with just a few taps, I can carry a bunch of them on my iPad and it doesn't make my purse heavier, I love being able to select a word or phrase and find out its meaning, highlight it, add a note or search... For people who have vision problems being able to change the font size and contrast are great features to have too.
So while I'm not thinking of giving up real books anytime soon I'm also enjoying iBooks more and more.
EDIT: I definitely prefer the iPad for textbooks though.
But iBooks have a lot of advantages: I can get a new book with just a few taps, I can carry a bunch of them on my iPad and it doesn't make my purse heavier, I love being able to select a word or phrase and find out its meaning, highlight it, add a note or search... For people who have vision problems being able to change the font size and contrast are great features to have too.
So while I'm not thinking of giving up real books anytime soon I'm also enjoying iBooks more and more.
EDIT: I definitely prefer the iPad for textbooks though.