So here's my impressions so far:
When I first put on the headset and fired up a game or two, I thought the sound was quite hollow. The positioning is absolutely astonishing though...100% accurate.
With My X-Fi card, I used the Equalizer to raise the midrange a bit to stop the hollowing effect.
What I'm stuck by the most, is how much I have to now deal with in games, when using these there is a massive jump in sound detail. The Base and Top end are super strong so you can hear things from miles away and the positioning being spot on, means i know exactly where it is. Having to deal with the shear amount of sound information is initially overwhelming...but after a few hours of gameplay, it's become clear that these are in a bit of a league of their own.
After the initial disappointment with the hollow sound, i was almost immediately convinced that this was NOT going to deliver, but having played for a while, I can honestly say that positional accuracy and adjusting the EQ with the X-Fi makes gaming a whole new experience.
Also the noise insulation is quite strange, I'm used to using the in-game VOIP and being quite able to talk with the MIC muted in the audio control panel. Now though, I've had to un-mute the mic so that I at least get a small amount of "what am i saying" cos the insulation is so very good. I kept having that feeling that nobody could hear me, coz i couldnt hear myself - strange experience that.
So, my initial opinion on these after tonight - is WOW 100% positional accuracy, however you need to get used to the change in sound since theres so much of it from all directions.
Can test the mic later