I am heavily biased in favor of books that can be downloaded & saved locally.
I got a late start on Google Books, but am catching up. This looks better than Google: I like that it's an "Open" enterprise. I am a near-rabid Open-enthusiast.
I will also use in-book search to locate specific information & references within books that I can't acquire & keep.
I have not participated in Google's 'engagement' scheme, but I am going to have a whirl at it, here.
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