Can someone explain exactly how these work? Are they essentially a USB sound card with attached headphones/mic, or do they somehow use your system's internal pci sound card/integrated sound?

I always thought they were the former, but I'm seeing a lot of "gamer" USB headsets and have been wondering how this makes sense since most gamers have a dedicated sound card and wouldn't want to bypass it.

I have a headset like that. There is a little USB attachment for plugging it into the USB port, and then it uses its own little sound card on the cable. The sound is 10x better when I skip the USB card (if you could even call it that) and plug the audio jacks into my real sound card.

The USB part does off weird simulated 7.1 sound. For a sacrifice in quality, I can hear which way the enemy is walking towards me. It's really not worth it, though.

USB bypasses any sound card you have on your system. This could be good if you don't have a soundcard yet, terrible when you do.

Basically audiophiles will hate the USB without a DAC/amp combo for their headsets, which none really exist for cordless stuff. To keep from getting toooo in depth, your source will have it's own card, which will most likely be as good as an integrated soundcard, but could be wireless (bluetooth) with a lack of quality.

Alright, that's what I figured. Thanks guys.

the only advantage I see is not having to reach to the back of your case and unplug your speakers/mic every time you want to use your headset.. But lots of the new mobo's will have integrated sound with ports on the front of the case anyway so *shrug*