There's really nothing wrong with the collet as long as it's the right one. They make them in different sizes and if the 'smith at Colt did his job right, it should never give you any problem. It will eventually wear and need to be replaced, but it takes a lot of rounds to do it. Rate of failure? I've been building them since a long time before they made the collet and so far I've seen exactly two fail. One wore out and one was fit wrong. One thing though, when they break inside, they're a bitch to remove.
Mr. Brown has it.If they aren't fit correctly to your slide and barrel,the fingers are forcefully bowed in the middle.Next thing you know it breaks.They are a nice idea,but a properly fit solid bushing will do the same function with a stronger design.Personally I don't see a need for one other than uphold the value of a 70 series.