I use both.
My .357 Rossi M92 zeroed easily @ 100yds with the bolt peep and the issue front sight.
I use the tang sight on another rifle, in conjunction with a folding rear bbl sight and the issue height front sight, to achieve two different zeros - a short range zero (say, 75yds) with the bbl sight, and a longer range zero (say, 125yds) with the tanger.
In use, I hunt with the tang sight folded for quickly-presented game shots with the rear bbl sight, and have always had more then ample time to raise the tang sight for game sighted further away.
In truth, though, I'm beginning to dislike more & more the thumb/grip disruption caused by the tang sight base.
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