I don't know if you are asking about fiber optic sights in general, or specifically about the Williams' sight.
I can't speak to the Williams' sight, but I do use FO front sights on all the revolvers I use in competition - they are a real boon to aging eyes, but of course work equally well for anyone. The greatest efficacy is outdoor use, where there is more ambient light. But they work well on well-lit indoor ranges also. Even in poor light, the worst sight picture you have is akin to a black Patridge blade.
I use both Dawson and HiViz. Dawson has a wide variety of sizes in both height and width, and if their workload allows, can do custom sizes. I like that there is a great deal of exposure of the light tube, which gives the brightest result. I also like that the light tube is easily changed should the need or desire arise. Some of the HiViz sights use a clear epoxy overmold, which makes them more rugged, but precludes changing the light tube. While they have several heights available, they are only available in a .125" width. I have never broken or lost a light tube from either brand and that's through thousands of rounds and hundreds of Kydex holster draws.
I apologize for not answering your specific query, but there are only small differences between one FO sight and another, in actual use.
Adios,
Pizza Bob