Digital accessibility experts are often asked about the usage of screen readers and assistive technologies. For example, one will often ask “What’s the most popular screen reader?” This is difficult (if not impossible) to determine technically, but also has privacy implications and other problems.
The following two surveys provide great data and are provided by very reputable organizations. Keep in mind though that the respondents were not controlled and the sample sizes are relatively low.
Although I feel that the iPad is certainly better than Amazons’ Kindle, I believe that the iPad will not “kill” the Kindle, mostly because of the price difference. The iPad is much more expensive ranging from $499 to $699 while the Kindle is $259. For more on this, check out Apple Tablet Could Be A Kindle Killer.