I've used them on a bunch of guns but never a springer. For stuff you can see well it's as good if not better than a scope. For 10 meters maybe better. You eyes just naturally center the sights. The main problem is target aqistion is slowed down a lot. Not great for hunting but excelent for paper punching. You naturally look through the hole so it's harder to see the whole picture.
Some types of apature sights are OK for hunting but mount further forward on the reciver. With a CZ .22 rifle I can hit small objects, like broken parts of a clay pidgion pretty consistently and a whole clay prdgion just about all the time at 100 yards with an aperture (peep) sight. They are much, much better than most open iron sights I have used.
The Gamo iron sights are some of my favorites though.
I really like aperture sights. Given a day of shooting at the range I'll often take an aperture equipped gun over a scoped one. It's just cooler frankly. Any kind of iron sight is cooler than any scope. I know that not real scientific but it's really Steve McQueen. Plus, when you're shooting stuff well next to the guy with the 4-26 Zeiss, well do I really need to say?
If you can see it you can hit it. That's the limitation. A well made aperture sight looks sort of byzantine. It looks cool in a WWI sort of way.
A scope is better for shooting green shotgun shells against a green background though, something that happens to me a lot. For paper, depending on teh pattern of the target as printed. (some targets work better with diffrent aperture patterns) it's just as good at reasonable ranges.
This said Ihave have some sights that worked great for me and some that I couldn't use.
OK. back to work. \
Adam