Oxygen has a lot of great ideas and elements that make for solid science fiction.  The premise is simple enough but feels all too plausible in a fundamentally capitalist space-faring society.  The story gets a little weak and self-indulgent in a way only Moffat can be at the end, with the Doctor almost brushing aside capitalism with a few simple moves and suddenly going blind.  That stuff feels a little forced and silly in an otherwise tight and menacing experience.  Either way, in spite of some faults this was a solid experience and a great example of Doctor Who using politics pretty well - Capaldi gets to be a real punk-rock badass in this story and Bill really goes through it here.