I typically go through ear buds pretty quickly. I keep my phone (iphone and now droid X) in my front jeans pocket, which means the cord gets pretty well kinked every time I sit down. Within about two months, the plastic insulation on normal ear buds splits, and soon after that the wires break due to the now sharper kink angle. The Sonix 3 ear buds have a braided nylon cord which is better able to cope with being kinked in the pocket. Also, the 3.5mm plug end of the ear buds is angled at 45� instead of the usual straight out or 90�, which helps protect the interface between the plug and the wires. I've also noticed that the braided cord cuts down on the static and resulting electric shock to the ear-drums that I get using other ear buds.
The downsides are the lack of volume control on the mic/button, and the average sound performance. I'm no audiophile and listen mostly to audio books and have no complaints whatsoever with these ear buds, but people with more discerning ears may notice the lack of head-exploding bass. Also, while the angled plug makes the ear-buds last longer, it does take up more space in the pocket as it's hard plastic instead of the usual flexible shrink-wrap stuff most headphones use. I think the plug adds about a quarter inch to the length of my phone.
All in all, for $20 I have yet to find more durable ear buds than the Sonix 3. Worth the very small cost if you want sound-isolating ear buds and are tired of having to repair the cord all the dang time.
