Haven't tried them, but from the couple dozen threads about them over the last 6 months or so it seems like most agree it's more gimmicky than anything else. For an equivalent price you could get a higher quality pair of standard headphones with the cost concentrated on 2 drivers rather than 6.
Music would be better represented from a high quality stereo playback than 5.1 and a surround mode.
Game surround could be simulated through 3d effects from a soundcard.
Check out headfi.org for people that know a heck of a lot more about headphones than I do.
You could also try to look for past 5.1 headphone threads although the search function has seen better days.