Do people think it's worth getting a 598 if one already has a 558? Or should the move be further up the food chain, as it were.? If so, which Senn would be a nice complement to a pair of 558s? I listen to jazz, rock, country, bluegrass, and edm (I know, I know--how do those fit together!?). Many thanks!
Move up the food chain. The HD600's are $279 on sale at Amazon right now. Adorama had a great sale that just ended for an even lower price.