I used my magsafe charger for 2 years and the charging end came off. I took it to a local Apple store in Manchester (UK) and it was replaced with a brand new one - no problem. Inever was aware of any problems with the charger... but i was really impressed with the service i received. Yes - it was replaced free of charge. Thank you Apple.
Have had my 65W PowerBook G4 mains adapter since Jan 2006 and it's never missed a beat. Innovative design with the detachable extension cable. Also with the ability to plug the power brick straight into a socket which no other manufacturer that I know of has. Flip-out cable coiling hook things (cable management hooks) for the low voltage cable are quite good but a detachable cable would be a better alternative. My 2005 power adapter has a design flaw though and, looking at this latest one, it still has it! The low voltage cable comes out the FRONT of the brick (when it is plugged straight into a socket). If it was on the BOTTOM of the brick it would look better, be less prone to damage and take up less space behind furniture. Apple could take a design cue from UK mains plugs on this, the design of which was well thought out, unlike the plugs in most other countries. Also, as I said, having the cable detachable would be better for transporting the adapter and reduce the likelihood of damage further!