A number of my bullseye-shooting friends use them with great success. They seem to me a little more reliable than the Kart units (I could never get my Kart to shoot reliably, tho I know others who have). I wish it locked open on the last shot, tho the Day conversion was quite popular and it didn't, either. Accuracy is superb. I shot next to one of the Marvel guys last year at Perry and he said they test each unit for accuracy, and fine tune the muzzle crown until it passes muster. The Ceiner/Kimber units are fun, but no where near as accurate as the Marvel.