At first I thought, this one is pretty easy, if you are deciding on the FIREWORKS alone. As I thought a little more on the subject, it occurred to me that personally, our evenings aren't based on fireworks alone. Our evening plans are based on a combination of factors, including but limited to: where we are staying, ease of post-show transportation, dining, what my group wants to do.
Personally, and this is just me, but I'd ask my companions what they want to do, where they want to eat, and what kind of travel woes they want to endure.
If you are staying at the Poly, and eating at 'Ohana, then we'd probably favor Wishes. If your resort/dining plans are at the Swan, I'd favor fireworks in that area.
If someone in my party has limited mobility or endurance, then ease of travel post-show climbs to the top of my priority list.