I still find a huge difference between ereader and physical book myself. I have a Kindle Fire, which I keep constantly in airplane mode and use no apps except Scribd on, but I find myself reading much faster on it, and also remembering much less of what I actually do read. And I can barely read pdfs on my mac, even with airplane mode and other distraction-reducing things turned on. I just don't like the format. I've come to realize I truly do best recall from physical books, and if I want to learn something new, I'll likely buy physical, though I might use pdfs for a while to test quality.