THE 590 are great
Paradigm: I truly like the HD590 and think they don't get the credit they deserve.
I sold mine since I have the Sony MDR-CD3000 ($450) but plan to buy another pair soon.
They are very detailed, and quite bright. I cannot comment with dance/Techno, since I used them mostly for classical/pop/rock. These cans excel with classical, and are usually not too bright even with the most piercieng ADD violins.
I also took lots of photos of my HD590, you could find them at Headwize.
Be sure to listen to them first if you're going for techno... the bass is natural, but I don't know if it will please you. I do know that they are excellent cans for classical, and sounded pretty good to me with pop/rock.
Overall, I love these headphones, they are a bargain at around $120. Yes, they are different from the HD600, but that doesn't mean they are worse in every aspect. Considering the price difference to the HD600, the 3K and other headphones, the 590 are excellent.
eric343: Well you said it yourself, your listening conditions were not addequate. I find hard to believe that the HD590 can be "the worse phones there" unless all the other are really high-end or you're not listening to a good model.