I like both, but I've always leaned toward science fiction myself. I have an easier time finding deep and thought-provoking stories in the science fiction genre, and I tend to prefer its more emphasis on exploring what its possibilities mean and using them to examine ourselves.
Fantasy. With sci-fi my brain either reflexively starts poking holes in all of the fake science stuff, or immediately zones out because someone decided to publish a physics textbook with a couple plot elements that start in chapter 15