it depends on how you'll be using them. stereo is usually preferred for music and some movie tracks, while surround is often touted in gaming. to be honest, it won't make that big of a difference, so long as both headsets are good quality. surround sound has advantages when directional audio comes into play - just think of any FPS where it may be beneficial to hear someone behind you, that kinda stuff.
the blacksharks are marketed as gaming headphones, and while many may denounce the 'gaming' moniker as nothing but a marketing ploy, I think it's at least reasonable to assume that the manufacturer intended for these to be used in that type of environment. in other words, I think you'd do just fine with the razers.