People who arbitrarily and capriciously claim that fiberoptic beads are worthless, useless, not the way to go, etc., apparently are quite ignorant that there are some of us that need these devices in order to use both eyes for shooting. The Uni-Dot in particular is a very useful tool for those of us who have issues with crossfiring. These same people also say you don't need a bead at all or even a rib. I'll believe that when I see trapshooters with K and P guns with round, ribless and beadless, barrels.
If you have crossfiring problems, ignore their ignorance and give a 2mm Uni-Dot a try. Realize it's going to take a month or two to get used to it, and your scores may drop until you practice enough. Those who try it for one round then declare it's useless are foolish. One key point is that you never look directly at the bead. You keep your eyes on the clay at all times and use peripheral vision to bring the dot to the clay. Your shooting eye will pick up the bead well enough without looking directly at it. If you look directly at the bead you will miss.
Keep in mind the Uni-Dot uses a tube to prevent the non-firing eye from seeing the bead. Regular fiberoptic beads do not prevent this.
If you don't have a crossfiring problem, that lessens the argument for fiberoptic sights. However, I find the bright bead useful under the lights at night shoots. And I especially like the bright bead when hunting.