I have two. One is a Colt Ace II conversion for series 80 guns. It took a lot of shooting to break in, and really needs high velocity rounds (Stingers) to work properly. Plus, it requires a special mainspring. However, it doesn't have the floating chamber.
My other is a Ciener Platinum Cup that I bought used from Ebay. It works well and I've shot over a thousand rounds at a time, using bulk Remington and Winchester ammo with very, very few problems. Usually, the problem can be traced back to the ammo. It may not be as accurate as some of the other conversions, but I'm satisfied with its performance. The Ciener does require special mags made by Ciener.