Music Theory? Learn it. Your always going to see a split of opinions when it comes to those who have learned it and those who haven't and say they do 'just fine'. I’ve had students when I used to teach who played just fine and didn't know any theory, and once I introduced them to it and they saw what they could learn from it, they do 'just great'. Knowing theory will enhance your musical ability ten-fold, amongst your appreciation for it. Why do you think players who go to school for music come out a way better musicians than they were before.

If you do decide to learn it. Remember to think creatively first, theoretically second.