I have a Ciener conversion kit (one of the first produced) on a Fed Ord frame -- I built this gun myself, from partially finished parts.
It's a plinker. Nice to carry and shoot, but nothing special. It will sometimes fail to feed on rapid double-taps, and has no slide hold open feature -- two things that make it a little less than perfect for practical pistol practice.
I also have a Colt Service Ace conversion kit mounted on an M1927 Argentine -- this is the all-steel kit with the floating chamber. This combination is far more reliable, has the slide hold-open feature, and is more accurate than my Ruger MKII.
If I were in the market for another conversion kit, I'd shop around and find another Colt Service Ace -- but for most uses the Ciener is perfectly acceptable.