ive only had the hd600 2 tw0 days, so take my opinion with a grain of salt. the hd598 feels flimsy and weak, its such a shame because they are one of the nicest phones ive ever seen in pics. in the flesh they arent as nice looking. whereas the hd600 looks and feels durable and well made. the marble finish looks alot nicer in the fresh 
and sound wise i strongly prefer the hd600 







