Half Round or U-Shaped Rear Sight Notch

Is anyone using one of these?  The idea of them is that imperfections in sight alignment become more obvious since the space on either side of the front sight change width and height at the same time.

Link to Nygord

Many of the European match pistols have the U notch option. I used to shoot U notch with my free pistol. Theory as told to me by Olympians at the time was that the U portion was similar to half of a circle. The eyes would naturally try to center the front sight in the U notch. I liked shooting shooting with the U. I don't think the current Bomar/clones can be adapted to U notch because there is not enough material to remove before the sight would run out of necessary height to have a clear U notch sight picture. Is there that much difference??? I don't think so. I shot international full time from 89-95 with both types of sights and think it doesn't make that much difference.

Jon

I use the U notch on my Free pistol because I like the concept and it came with some, but I can't claim any evidence it is better or worse than the standard rectangular sights.