[rant on]
I'm getting really frustrated with these. I've just gone through my third one in less than three years. Each one died the same way. The tiny springs behind the pins corrode because of the salt in the air here (I live a few feet from the sea). The pins then no longer make a snug connection. This causes heat. heat kills.

Don't get me wrong, they are a fantastic idea, and have saved my notebook from drops several times over, but I wish there was something they could do to keep those springs in good shape.

At the very least they could sell the MagSafe connector for the end of the cable. I'd happily pay $10 for the connector and replace it myself rather than having to shell out $45-$80 (retail) for a new power adapter every time. I've got three perfectly good ones with ruined tips sitting in a box.
[/rant off]