I've found that an e-book whether in the form of an ipad or Kindle like device is great for reading for pleasure. Novels and News articles fly by for me.

However, when I try to read any technical book on my Sony reader, I feel frustrated. I love jotting notes down when I'm learning, and I constantly flip back and forth between pages. Nothing beats a real book imo, and as much as people want to push technology in classrooms, I still don't think it's conducive to learning.