Considering how well the darker batman series was received and the positive reception if Capt America and Thor. I think MoS has nothing to worry about. It will do Warner Bros projected 500 million.
I myself am a huge Superman fan. Silver Age all the way through today. While Superman Returns was a classic age film it didn't inspire repeated viewings. Supes has been morphed into a go get'em action film for the summer. Superman Returns was a romantic drama film released in the summer of 2006. The times have changed and Superman has to also if he is to be relevant. Snyder said he approached this film as if it were a real scenario in our world. The light comic book fantasy doesn't play as well as it did back in the 70's-90's. Tough pill for us old school fans but we have to swallow.