Man of Steel premiered back in June of 2014 and grossed only $668 million. Rotten Tomatoes gave Man of Steel a 55% rating amongst critics, with 75% of fans stating they liked it.
I thought Man of Steel was a pretty good Superman movie overall, but I don't agree with Superman snapping Zod's neck at the end of the film. I had no problem with all the destruction, as a bunch of super powered Kryptonians would do just that, but Zack Snyder and David Goyer's decision to have Superman kill Zod was the wrong way to go, IMO.
Snyder also continued going the wrong way with Superman in Batman vs. Superman by butchering all the Superman characters in the movie (Lex and Doomsday were awful, killed off Jimmy Olsen for no good reason, killed off Mercy Graves who first appeared in the Superman animated series, and of course killed off Superman, etc.).
I hope now that with Man of Steel 2 in development they get somebody who actually "gets" Superman and is a fan of the character. Sadly, it's pretty obvious Zack Snyder is not and is pretty clueless (along with whatever producers were involved).