Superman always wins. My little guy always asks who would win the following and my answer everytime SUPERMAN.
Superman vs. Optimus Prime. Tough fight but superman would eventually disassemble him to the point he could not fight anymore.
Hulk VS. Prime. I was unsure how to answer this but my wife decided Hulk due to him raging and eventually incapicitating Prime.
Superman vs. Hulk. The best one IMO. Superman would eventually haul Hulk into space where he would asphyxiate. My wife and I disagree on this but we both know I am always right so.......
OH and sorry G I didnt mean to go off topic here but I felt like even starting this topic was somewhat a slap in the face to the man of steel given the other guy is just a cartoon and well superman is real..........Playing along though.
Superman vs. Whoeverthefkgokuis. Well....... Haaaa.. That would be like putting a 3rd grader into the ring with 1996 version of Mike Tyson or putting that same 3rd grader into Michael Jacksons slumber party club. Not good I say .....not good.