The current fireworks show is so much more then just fireworks. There are projections (bits of film shown on the facade of the castle or IASW). They go along with the music and fireworks. For example there is one part that has music and dialog from Haunted Mansion. During that part there are ghosts projected on the castle- they look as if they are floating up the front of the castle. There are also other pyrotechnics, lasers, music, tinkbell in flight etc- its a complete show, not just fireworks in the sky. It really is best to watch it from the hub, near the partners statue. That way you can see the stuff around the hub and between the matterhorn and castle. But, if you arent willing to wait, go to its a small world and watch from there.
F! is performed on the rivers of america. There is not theater type seating at DL for it. You sit on the ground (in roped off sections), or pay for seats and dessert. If you want reserved seats they are $59. They are available on the balcony of the gallery or riverside. They include a dessert buffet. You would need to book them 30 days in advance. They go quickly, so you need to call at 8 am the day you can book (if you wanted say June 1, you would call on May 1). They are prepaid and non-refundable (unless the show is canceled).