They are not much to look at. Very lightweight with a 4' cable ending in a gold plated, right-angled mini-plug. I've not used this sort of behind the head style before. They are certainly very secure there, but I'm not sure about long-term comfort. They press quite hard on my head, just above my ears. There's also the band, which you feel every time you move your head back. Maybe I'll get used to them. First I need an extension so that they can plug into the back of the PC.
I've tested them so far with the Palm and a laptop. The sound is pretty good. It's very clear and there's enough bass for my tastes. My reference tracks are Pagan Poetry by Björk for it's mix of quiet and loud voices and All in a Day's Work by Eels for it's driving bass drum. That drum was really kicking me in the ears, but was perfectly defined. I can also still hear what's going on around me, including the phone ringing. They can be heard from across the room when turned up.
I'm reserving my final judgement for now until I see if they get more comfortable. I did try them upside down. This removes the pressure whilst staying in place, but I'm not totally convinced. I'd say that, for the price, they are very good value, but maybe you should try them on first. My colleagues are free to try mine out.