I have had brass bead front sights, gold bead front sights, and varying black or tritium sights.
The best and fastest one for carry or duty guns to me is the Ameriglo or Trijicon tritium front sight with a big orange polymer ring around it. Easy to pick up in any light and the front sight just stands out so sharply. Not as fragile as the plain fiber-optic sights, and much brighter than gold or brass beads.
However, gold or brass bead sights never need to be replaced, so I like to have a gold bead front sight on the pistols I mainly have for collector pieces. Currently that is only one pistol, though, but if I ever ordered another custom build, I'd probably go for a gold bead.
I will say that gold and brass do not seem equal to me. Brass tarnishes and gets dull faster and doesn't seem as bright even when clean. Gold seems brighter and polishes nicely. If it's a domed bead, I find that better as well, as a flat one mainly reflects light straight back and is most reflective from a perfect sight picture, while a domed and polished bead, for me anyway, is picked up more readily from imperfect sight pictures.