I'm looking at the key-hole system and the Murray's catalog (p 46) shows three different ball setups; the original key-ball-on-a-wire connector, a "can't miss" ring and a "can't hurt" loop. Catsailor.com lists two and the Bethwaite site shows an additional variation of the key-ball-on-a-wire connector.

Looking at the different variations, I have a hard time seeing why one would be considered can't-miss, another can't-hurt and how either could miss or hurt any more or less than the original.

Does anyone have any experience with the different connectors?