On my iPad I have a collection of 15 or so books and have completed one solely using the device. It was a great experience and well worth the low price of free for the iBooks application. However, having bad eyesight is a mere understatement and I've recently been lusting over the crisp, clean look of e-ink. I caved, picked it up at my local Best Buy and loaded my Amazon collection.
Since day one my experience has been nothing less than a reading extravaganza, some may even call it a Festivus miracle. All in all, if you're a bookie and have a hundred bucks to spend, grab one.