No contest, I prefer shaved or at least neatly trimmed. I really, really hate getting pubes during a BJ. Shaved balls and down the shaft is ideal (& hair above trimmed enough my upper lip and nose don't get tickled too much), but very neatly trimmed around the area is okay (although with a little practice, shaving isn't scary. Use a blade that's well broken in and dulled a bit by your face, not a fresh blade straight out of the package, and pull your sack this way and that, up and down, side to side, in order to provide a somewhat flat surface for short strokes, & much easier to shave if trimmed with scissors first; I encourage you to give it a try, as shaved balls are hard to resist and will invite a lot of attention compared to any amount of hairy).
It was actually a wild old girlfriend who'd been into swinging who told me in no uncertain terms that if I wanted my dick sucked and my balls licked regularly, I'd better shave and trim, or she and most others who come along will assume I don't really want that service. In the years since dating her, having become an enthusiastic cocksucker myself, I agree wholeheartedly.
Here's a different question: I'm a late bloomer and haven't accumulated a huge number of organs yet, but in my experience in general the white guys I've sucked are shaved, and the black guys I've sucked are hairy bird nests. I much prefer black cocks, but a lot of hair really takes away from the total enjoyment. Has anyone else noticed the same thing in their experience?