I just shot a Ruger Blackhawk with one of these the other day. Well, it was actually nearly the other night, so I couldn't see too well. It was good for picking up a fast sight picture, or would have been if there was more light. I was also partially blinded by the muzzle flash of the gun, which didn't help. All I can say is, whatever powder Wilbe Lead was using in his 357-44, the orange fireball sure lit up the night.
I've also tried the wide-v, express style sights, besides standard factory. They all work, once you get used to them.