Surround sound headphones are definitely a gimmick. Laws of biology and physics simply don't allow the human ear to process positional sound (aside from right and left, of course) from speakers positioned so close to the ear. You need to have speakers adequately spaced apart and at multiple angles for any true positional sound.
Anyways, the PC350's you went for are an excellent choice and as good as you're going to get for a headset (headphone + microphone). I believe they use the same drivers as in the HD595's. You're good to go.