Very good and useful. The only questionable fact is "If you do 10 hours of reading a day", it seems to much. I'm working 16 hours a day and I can't imagine using e-reader for 10 hrs, it completely different than staring at PC screen. But if I put it in a personal perspective, say 2hrs reading before going to sleep, that would be five times more, 20 - 25 days. Which is really good
