Yeah, I have. It was nice as far as it went, but *very* limited and basic features. To give one example aside from the lack of reading style adjustments, annotations--something I use a lot--are not accessible or exportable. They are tucked away in a magic client-side database that MSFT keeps well obscured, and used to sync between your various devices. And you cannot upload sideloaded epubs to your Microsoft account, as you can with Google Play. The combined ebook 'ecosystem' that comprises Edge browser, the Microsoft ebook store, and your personal Microsoft account, are a weak and subpar offering compared to any of the other established players. Although I love Win10 as an OS, it's a bummer to see them not taking touch-optimized apps, and specifically the ebook reading experience, more seriously.