First off does the headset use a sound card and have a line for each channel? If it does it's actually not a digital it's analog. Digital is where the surround is simulated and only has one line into the phones. From what I've read these sound like they're analog.
Anyway I've tried so many analog cans it isn't funny and I've finally found the ones I love with my current pair.
My problem wasn't so much the positional aspect of any of the headphones I've tried, they ranged from okay to great. It was using them with a stereo source. They all sucked and had no volume at all. Who ever designed the Tiamats thought of that and you can switch the 7.1 to 2.1 whenever you need which makes all the difference in the world.
Price? Well yeah they cost a pretty penny, but they're well worth it because I'll never have to get another set.