the special edition (598SE)are just regular 598 headphones but the all black color and with a second shorter cable instead of just one like the original 598s. There is no such thing as a s model, it's just the plural word. But there is the 598cs, maybe that's what you mean, those are more or less the same headphones but closed back, with sleeker pads and lower impedance so that they're better for the outdoors I guess.
I havw them, I am sure. Read my full reply i sent the first reply halfway by mistake!! I think sennhesier dropped the price of the se because they had so many in Stock and they want to sell them all now that they stopped making them and moved on to the 599
they dont sound better nor worse, they just sound closed while the original pair sounds open due to the fact that they are closed and open respectively. There is no better just a matter of preference. Some people want the more open and airy sound of open cans and some want it more concentrated or they don't want any sound leakage so they opt for closed. It's up to your needs really
you won't find a big step up in this range I feel. I'd suggest waiting till massdrop rereleases the 6xx and buying those, or if you want something different, the fostex 50 mk3
