For recreational reading, I strongly prefer real, printed ones.
For reference materials, I strongly prefer electronic ones (stripped of DRM and converted into a non-proprietary format). I can keep my entire technical library on my phone and I can grep through the entire set of books for something in particular that I need to find. I remember the days when my technical library was in printed form. It took a lot of space and often I'd be unable to predict which book I'd need at home vs at work, and end up not having it available. On this front, electronic books were a total game-changer for me.
For recreational reading, I strongly prefer real, printed ones.
For reference materials, I strongly prefer electronic ones (stripped of DRM and converted into a non-proprietary format). I can keep my entire technical library on my phone and I can grep through the entire set of books for something in particular that I need to find. I remember the days when my technical library was in printed form. It took a lot of space and often I'd be unable to predict which book I'd need at home vs at work, and end up not having it available. On this front, electronic books were a total game-changer for me.