Since the creation of the iconic characters, Batman and Superman, there has always been a war surrounding the question, "Who is better? and Who would win?. Even after reading this post this question will never be solved. So, just consider all theories and you make the judgements because thats the entertainment comics are made for. Now my previous post and my username may make me seem biased, but I will be fair lol. I personally believe Batman will win. None can kill the other, but they can inflict almost fatal repercussions. 
Superman is considered to be one of the most powerful heroes in the DC Universe. His vast array of powers really do make him almost impossible to kill. However having these powers does not mean he can beat everyone. His weakness to magic, kryptonite and red suns are existent, but what people overlook is his personality. No matter what, Superman wont kill. The only time Superman has ever really killed someone was Doomsday, which resulted in his own death as well. His good nature is so strong that even when he is in rogue mode, he wont ever cross that line. When people often say "he can just flatten Batman in less than  2 seconds", they are wrong. When this argument is used its no longer a Batman vs. Superman battle. Superman's inability to kill is considered one of his weaknesses. Without counting that, Superman is no longer Superman. 

The next argument is Batman's prep time. People always believe that without it, Batman has no chance. Although, within the pages of Hush, Batman required none as he already kept them in his belt without completely being aware if Superman may or may not arrive. The other argument people make are the writers. When Batman is shown defeating Superman, everyone's immediate reaction is to blame the writers. I dont understand how this comment can be taken seriously. The writers are the ones who create the characters, so that means if the writers are wrong then the character in general is wrong and therefore no point in them even existing. 

Another aspect, which is actually a defining point in Batman and Superman's relationship is their trust. Superman is the one who entrusted Batman with the kryptonite ring as a means to defeat him if necessary. He could have picked anyone else; Diana or Hal Jordan, but it was Batman because he knows he has the capabilities to do it. Also, Batman acts somewhat like a robot, he is constantly learning and analyzing every move Superman makes. Yes, Superman's power can defeat Batman, but Batman has perfected in evading and controlling him during a fight. But, Superman is no idiot, he does have super intelligence but in a completely different aspect than Batman. Superman can remember almost everything and can identify and understand and create technology. But Batman's unpredictable mind knows how to use it in ways Superman has not analysed or thought of because Batman knows exactly how his brain works. This is the main reason Superman knows if anybody, its him who can defeat him. As quoted by the Man of Steel himself "Batman is the most dangerous man on Earth".