The Steyr M-A1 has these kinds of sights... on the particular gun
I was shooting, I found that while they were fast, the practical
accuracy wasn't that wonderful. It was too easy to mash the
front into the rear visually.
And at the end of the day, I found my accuracy with the gun was
more affected by trigger control than anything else.
I've found that it's hard to beat simpler, more practical sight
systems... it's hard to beat a mono-dot with a notched rear type
sight, etc. Course, everyone is different.... one sight someone
likes, someone else will hate, etc.
-Mike