Mouse and keyboard is so superior to a controller it isn't even funny. Personally, I love playing with a controller as opposed to mouse and keyboard, and, I love the fact that everyone is GENERALLY on a level playing field in console games. This is despite the fact that I have played at an elite level with a mouse and keyboard but am only an average console gamer.
Even the best players in the world with a controller can't compete with players with a mouse. The mouse gives you better control, which should be clearly obvious to anyone who has a lot of experience playing with both.
Moreover, you can play with super high sensitivity with a mouse (and most pro gamers do), whereas you have to play with low sensitivity in order to have superior accuracy with a controller (and most pro gamers do). High sensitivity, however, gives you some advantages which simply aren't available to a controller player without sacrificing accuracy.