It should be no surprise that I use the Kindle software. I prefer reading on an actual Kindle, but about 2 months ago I broke the screen on my kindle and have not replaced it. I am being intentional about this because I have a good number of paper books I need to read and I have both an iPad and an Android phone on which I can read my kindle library. (And my wife has a kindle if I want to use her’s.)
As good of a system as the Amazon Kindle world is, it does not have nearly as many public domain books as Google Books. Google has invested considerable resources into scanning all of the books of many major libraries. There are about 3 million public domain books in the Google library. This dwarfs any other public domain collection. As a system, I think Google books is pretty good. I am not going to leave Amazon, at least in part because Google’s selection is smaller and price seems to be a bit higher. Google was depending a lot on their agreement with the Author’s Guild to make their system the world wide leader in both paid and public domain books. Since that agreement was blocked in court, Google is far behind in the recent book department.
This video is a pretty good introduction to how Google conceives of themselves.