iPad and Kindle Reading Speeds
Jakob Nielsen did a short study comparing reading speeds of iPad, Kindle, and the printed book:
The iPad measured at 6.2% lower reading speed than the printed book, whereas the Kindle measured at 10.7% slower than print. However, the difference between the two devices was not statistically significant because of the data's fairly high variability.
Thus, the only fair conclusion is that we can't say for sure which device offers the fastest reading speed. In any case, the difference would be so small that it wouldn't be a reason to buy one over the other.
But we can say that tablets still haven't beaten the printed book: the difference between Kindle and the book was significant at the p<.01 level, and the difference between iPad and the book was marginally significant at p=.06.
I think it would be very interesting to see more in-depth studies like this where reading comprehension is also measured. If higher education ever intends to move from print books to eraders, it would be good to know the potential effects on reading comprehension ahead of time.
BTW: Bought a Nook. My last experience reading a book on a small handheld device was my Palm M505. Gotta say what a much better reading experience with the Nook. After I've had a chance to use it more, I'll post some reflections. In the meantime, it's an impressive device for only $149 if you don't yet have an ereader but want one.