Chiming in with the others to say that my experience with e-readers has been great. Physical books can grow to be a huge burden over the years.

For me personally, e-readers have not caused any loss of focus. In fact, the integrated dictionaries often keep me MORE focused than the interruption represented by pulling out a dictionary or googling a word.

I'll acknowledge there is a tactile joy to physical paper that is lost when using an e-reader, but for me it's well worth the trade-off for the the portability and space saved.

Also consider that often, people who are expressing skepticism of digital reading have only ever tried it on laptops and iPads, which is a very different (more distracting) experience from an e-ink reader.