I am in desperate need of a new gaming headset, and I came across two well-regarded headsets. On one hand, I found a pair of Sennheiser gsp 300's at a local store for $80 and on the other hand I found a pair of Sennheiser hd 558's at an online retailer for $85 (including shipping). My priorities are comfort (I don't want a headset that clamps too hard, for I wear glasses) and being able to provide an immersive gaming experience that I can easily get sucked into and forget the outside world. I would like to know which of these headsets (each with a totally different design, the first one being closed-back and the later being open-back) can provide this experience more properly (BTW while having good music quality would be a plus its definitely not in my list of priorities).