I've had several mags with and without CS springs with no discernible differences. I did notice a huge difference between CS and SS springs when I replaced the recoil spring on my 1911. I load a bit hot so I would only get 1000 or so rounds before needing to replace a SS spring. I switched over to a CS spring and 3000 rounds later, I'm still using it.
The CS spring in a magazine is extremely good. It will not take a set and will last much longer than a SS spring. I know guys will say that you would have to put 50,000 rounds through a magazine to have the SS fail, and they are right, but at the same time the SS spring is losing power over time where the CS will not.
CS springs used as buffer springs is a great application and use of a CS spring. CS springs were developed originally for anti-aircraft guns. In testing the CS out performed the SS hands down.
Larry
C Products