First think came to my mind. I am reading textbook for a course I am taking. I am not taking any paper notes as I just highlight and take online note on Kindle Reader Webapp/mobile app. I would be devastated if I lose my bookmarkings and data.
This article made me aware of it. There are not many quality options. Amazon Kindle is an amazing product. For example, Neuroscience Exploring the Brain by Bear et al. is not available on Google Play and is $30 over on Barnes and Noble.