I watched my '24 Season 2' DVD set to sample a sound track which incorporates action, both heavy and classical music, and of course speech, to test these out.
The full 5.1 effect is clearly present whilst watching and listening - sounds can be heard from the full 360 degrees, which is quite impressive considering just how close your ears are to the source of sound.
From a sound quality point of view, the sound isn't brilliant. Mid range frequencies (especially speech) sound as if they're coming at you through a drain pipe, and there is a distinct lack of bass. This is possibly due to the large cavity inside the headset. The cavity means that if you are used to listening to a high quality set of headphones such as those made by Grado, Sennheiser, Beyer etc. then these are not going to get along with your ears very much!
I also listened to these for a good evenings worth of computer usage, playing both games, listening to music (as well as the DVDs mentioned above) and they were comfortable throughout, once I had learnt to ignore being able to see them in the corner of my eyes - the front of the oblong housing for the speakers is clearly visible in the corner of both of your eyes - something which I found annoying.
Good buy or not? Well, they're great for LAN gamers. They're chunky and would take quite a battering, do their job as far as surround sound is concerned, but lacking the quality - which is not always present in games, and which can be difficult to discern over the hubbub of a party!
However... for a retail price of ~£60 these are definately not worth the money. For £60, the sound quality is just not good enough. Yes, you get the effect, but my Sennheisers sound better by 100 times. No amount of EQ fiddling could get these Zalmans sounding to my liking.
Maybe Zalman will do something in the future to improve the sound quality of these headphones? I personally would not buy these until such improvements have been made, OR you simply don't care too much about quality - perhaps your existing pair of headphones are not too great either? ;)
Verdict: 5.1 effect is clearly present, fold nicely, funky for LAN's, but with the lack bass and clarity, you can do a lot, lot better for the price.