I've had two of those catch on fire from where the wires became exposed near the RCA + 1/8" headphone jack connector.

This is the same design used on older (circa 1994) Powerbooks, like the 520.

Here is a generic adapter for a 520. You can see the same connector...

http://cdn1.iofferphoto.com/img/item/138/470/449/Hsai.jpg

It's interesting that the older ones DID have the vented / slotted strain relief sheath.

I wonder how much more expensive that is to manufacture vs a stylistically cleaner, simpler solid sheath.

And despite the article author's claim, the old style connectors also frayed, usually right at the strain relief. In my experience, while the magsafe style strain relief isn't perfect (it's showing a little wear after two years), it's lightyears ahead of the old barrel connector which required replacing every 9 months.

Injection molded plastic? I'm guessing the cost difference is negligible or non-existent.

I had a 2005 PowerBook with the same adapter, and, despite the slightly better strain relief, it still broke after a few years. And, like another poster mentions, it caught on fire (tiny tiny fire, really just the next step up from smoldering). That was... not so awesome.