The two things which modern devices do better than traditional paper books for me are mobility (having my whole library with me at all times) and inbuilt dictionaries. At everything else they are worse. E-ink comes quite close to a book in how pleasant it is to read; an LCD screen doesn't add anything with its additional functionality and staring at the screen for a long period of time is painful. Not to mention the poor battery performance.
I have used my phone for reading on the bus. Nowadays this isn't a problem since I have an e-ink phone
