HD600's are $299 from an authorized dealer. https://www.buysonic.com/products/sennheiser-hd-600/
I'm considering it. Thing is, I had both the 598 and 600 in a cart before deciding on the 598. When I searched for 598 vs 600 threads here, I found that a couple of people thought the 598 were close to the 600, and had its own benefits (wider soundstage, for example). It might have been hyperbole on their part, not sure - but I figured if the 598 were in the same ballpark, might as well go for the cheaper option.
I would advise you to stick with them. I know it's hard when you have a window to return them, but it took me months to get used to these, again like you, coming from faster/brighter headphones (Grados), but now I appreciate that they have qualities that no other headphone has. I would never get rid of them now, despite purchasing 'higher end' cans since then. It's not either or for me with choosing headphones, I have a number of different ones for different listening purposes. You will find it harder to get a more liquid and beautiful rendition of female vocals/small scale acoustic stuff for the price of these. My go to relaxing headphones, which my Grados are certainly not!!
Yeah...I'll try to get as much mileage with these headphones in the meantime.
Edited by grandcross - Today at 4:52 pm