So, I'm having some issues with ebook metadata, not displaying in DOpus. I can't get any of the metadata to display in the columns in the browser, but in addition to that only extended and standard properties show in the metadata pane when I select my ebooks.
Opus should show some fields for PDF files (unless they're protected). ePub and Mobi formats aren't supported, although someone could write a plugin for them.
Thumbnails and Cover preview may also be useful to get information about ebook files. For the epub format follow the instructions for Win 7 on this side. Also working for me on Win 10 x64.