I talked with Scott Warren about his sights several years back at SHOT. I had heard about them, but hadn't seen any. He was adamant that the rounded bottom corners, with the flat bottom, was superior to an actual U-notch.
I've got his sights on a couple pistols and they work fine for me. I basically look at the top of the sight picture and the bottom of the notch doesn't enter into it.
Rosco
I loathe the U-notch. One of the reasons for making the "Pepperoni" Wilson Combat Beretta rear sight...
That said, I recall Y'ur Yev talking bout this in his enormous tome. (If you're not into bullseye, forget digging it up...) I seem to recall him specifically saying that for large FS (where the width is proportionally "the same" as the bullseye at 25m), a narrow U-notch would help guide the eye to the top right edges. I.e. having less 90-degree "corners" would allow the eye to focus on the most important 90-degree corners (the top of the sights)
With competition pistols, and enormous notches, where we crave the flash sight picture, not having straight angles is confusing...
BTW - a good thread on Enos is here: http://forums.brianenos.com/topic/15...ights-we-have/
Stuff has been around forever. In the current iteration, the idea was that the human eye likes to align circles, which is what the original AUG optics and HK diopter was all about. I have found this true with my eyes and what they prefer. Place a big dot in he U and the rear will help the eye to center the dot for those of us who like to drive the dot. The top is of course flat, which also allows for more traditional precision work with traditional alignment on the top half of the sight if the shooter wants that. Much of his is eyesight and training dependent.
Just a Hairy Special Snowflake supply clerk with no field experience, shooting an Asymetric carbine as a Try Hard. Snarky and easily butt hurt. Favorite animal is the Cape Buffalo....likely indicative of a personality disorder.
"If I had a grandpa, he would look like Delbert Belton".
I use the 10-8 fiber optic front and the 10-8 rear U notch on my P99's. They took some getting used to, but are very easy for me to align and get on target fast.
Before the 10-8's, I ran Ameriglo CAP's on my Glocks. Two completely different sight pictures, but the 10-8 gets the nod for my eyes.
"... And miles to go before I sleep".