If I can call a winner out of the set, I'm leaning to Amazon.
(I don't /want/ to lean to Amazon, but it seems to make sense.)
The problem with Google, Microsoft, and Facebook, is that what they're selling is ultimately what the /user/ does not want: ads.
Amazon, though, has what we really want: /stuff/. Food, clothing, furniture, books, movies, hardware, software. Some of which you absolutely need to live, and yes, much of which you don't (which means an incentive for over-selling).