Even my first AF SLR (an F65) managed to AF accurately on fireworks as have all the other SLRs I've had since then (film and digital). As usual, the centre focus point seems to be fastest and most accurate. Even in the relative dark, I find AF to be more accurate than my attempts at MF using an AF lens, although setting to infinity and lettting a small aperture's DoF absorb the difference works well too.