Terry Gilliam never makes a totally bad movie (except Jabberwocky, I mean omg). His movies always have a unique visual style and fantastical feel to them.
Though Zero theorem is one of the weaker stories he has told. At the end of the movie the bad guy has to literally explain the movies plot in a monologue, that's how bad the plot is. Brazil or 12 monkeys never felt the need to explain their own plot; you got everything you need to know from actually watching the movie.
So yeah, if you are a die hard fan of Gilliam you should watch it, other wise watch Brazil or 12 Monkeys.
Though Zero theorem is one of the weaker stories he has told. At the end of the movie the bad guy has to literally explain the movies plot in a monologue, that's how bad the plot is. Brazil or 12 monkeys never felt the need to explain their own plot; you got everything you need to know from actually watching the movie.
So yeah, if you are a die hard fan of Gilliam you should watch it, other wise watch Brazil or 12 Monkeys.