U notch sights are great for fast target aquistion. The human eye attracted to sharo corners and angles. So your eyes go to the edges of the sight notch at speed. With the u notch your eyes move to the sight faster. This is great for fast shooting at closer ranges like in defense and gun games shooting. Slower fire and bulleye shooting is not helped by the U notch. IMHO I prefer the U notch because I am not shooting for bulleye type groups.
I have completely moved away from 3 dot sight setups. For me they are not as fast. Again science tells us that the human eye will focus naturally on the dot closest to our eyes so with 3 dots too often that is one of the rear dots. If I am going to use a dot I blackout the rears. This is what works for me for many people 3 dots work better.
My go to these days is a U notch rear with a Gold Dot front.
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