(a) In a general 4-player game, is Saboteur a better card than in a general 2-player game?
(b) Extreme case: in a 4-player game where all three other players think Saboteur is amazing---will buy it and play it whenever possible---what is your best general strategy?
I take as given that Saboteur is a terrible card in most 2-player games (based on Isotropic data and the answers to the previously linked question; please direct disagreements with this assumption to that question).
I will actively downvote answers citing anecdotal evidence. @RobRenaud's comment in the BGG link is a good example of the type of answer I'm hoping for; I hope he submits it as an answer (perhaps fleshed out a little more) relatively soon, otherwise I hope someone else does. I'm also interested in well-reasoned arguments that agree or disagree with that conclusion.
And please don't make your answer too dependent on other cards in the kingdom set. Of course Lighthouse or Moat (or many others) could provide specific counters, but keep your answer general.