Perhaps this is because I've only ever heard about Amazon's march into publishing through interviews of authors and competitors, but the narrative I've picked up seems to revolve around Amazon actually being a terrible publisher. By which I mean you basically never know what you're buying if you're a reader, and they aren't spending a dime to edit or promote you if you're an author. (Not that publishers do those two things much either of late, but that's a different story.)
I suppose that's fine when you've a track record as an author. It probably isn't if you're a new author.
Any odds there are some authors around who can chime in?