Well, I have to say there is no real "best" one as it's a pretty personal thing, as in whatever works for you
some people just like a single white bead or a gold one, either one with or with out a short center post
Those 2 are probably the most popular historically
Glowing sights like the original "Raybar" introduced many years ago or the newer fiber optic ones have strong followings as well
I have used them all and have never found any of them made much difference to my scores as I don't really see the sight clearly anyway as my eyes are focused on the target.
I do "Notice" the bright fiber optic ones more but as said already haven't found them to make much difference where it counts.
If you "think" one particular type helps you than you should probably stick with it as even if it doesn't do anything in reality it would give you more confidence and that can be a big plus.