I've found the Medusas to be rubbish for surround sound.
They don't have front channels. IMO, that is rather a serious drawback for surround sound in games. They have left, right, centre, left-and-slightly-rear, right-and-slightly-rear. I also get "jumps" in games, i.e. parts where the apparent source of the sound in the gameworld will jump from one place to another as I move in the gameworld.
Quite crap, really. Nice idea, but I don't think it works.
I have found the Medusas to be very comfortable to wear, even on my big head.
Sound quality would be better on a similarly priced decent pair of stereo headphones, of course.
From what I've read, the fake surround sound on an X-Fi with stereo headphones works well enough to make them a better buy.