Single cord connection to the ear pieces
A bit bright
I think the best way to determine if these are the headphones are for you is for you to consider what type of music you will be listening to.
I bought the 590's for my mainly rock-n-roll interests, and was a little disappointed. The clarity was good but it lacked that "wow" factor, which I consider the most important part of the experience. I found that when the tracks really got motoring the vocals seemed to be lost in the background. The mid-range just didnt come through when they needed to. If your musical tastes are more towards classical or jazz, they may be a good choice. They did have nice warm bass, and crisp treble. At louder volumes they tend to be a bit bright as well.
My best advice is to find a dealer that lets you sample the headphones with music that you bring with you.
FYI...I switched to Grado 325i's and was very pleased with how they handled rock music....much better.