Or do what we did to guarantee a seat, and good music. For 8$ per person you can take a wagon ride through the park, and they take you to a remote area away from every one else to watch the fireworks, with the music.
There are some things you'll miss, 1. the "shooting stars" will go off behind the castle, so those will be in the distant 2. You don't get to watch tinkerbell fly 3. The fireworks won't explode behind the castle.
It's just little things like that can either can make it or ruin it for a person. I've seen the show from several locations, on main street, in frontier land, from FW, and I'm waiting to see what it's like from the contemporary. But if any one is afraid of the loud booms, it's best from the beach. Although there still are a few that do send vibrations up your back.