I'm looking for new headphones for myself with high sound quality! The usage is for gaming, music listening (and seldom some movies)... I've done A LOT of research and stuffed with all these reviews there are (Newegg, Amazon etc.).
I can't speak to the Roccat or the Medusa, but I have the Razers and they leave a lot to be desired. In my opinion the bass is almost non-existant and sound is overall pretty weak and tinny. I've heard nothing but good things about the Medusa.
You also may want to consider the Creative Fatal1ty MkII. Or, if you have an optical out w/ DDL encoding, the Tritton AX 720 (I actually just switched to these and for the price I think they're great; the surround is pretty convincing for a 2-channel headset and the sound quality is, in my opinion, excellent), or if you have the money, the Astro A40s w/ the amp. These three were fairly highly rated in the recent gaming headset review (http://www.tomsguide.com/us/pc-gaming-headset,review-14...) and I am really happy with my Trittons at the price. You can only get those at Best Buy though so that may be a factor in your decision.