The Sharkoons also have the full speaker layout for True 5.1- the sound field is incredibly accurate for a cup-based speaker system, it's the reason I bought them; they're in completely different league to the Medusas and especially the Razers which use a form of speaker virtualisation to generate the field.
The width of the sound field can also vary depending on the output of your sound card, I receive a much wider and more accurate sound field when connected to my X-Fi than when I use the onboard sound and this can be tweaked the personal preference through the software. I'd be interested if the speakers were of a higher quality technically speaking than the Sharkoons but I doubt the bass will carry the same punch due to the more open design.
If I remember right these are the ones that provide the bass vibration through a series of smaller sub speakers in the actual headphone bridge, correct?