Very accurate - only pretty when the mix is.
I got these and have to admit that they didn't impress me at first listen. Then I took a trip to Headphone.com and found out that these cans and their big brother, the K701's, require a significant break-in time, on the order of 200-300 hours. So I broke them in for the specified time, and 10 days later, the results were significantly better.
I have been trying to objectively decide if the bass response is under-represented, since most headphones have a hyped bass response, and I still can't decide. I frequency response curve I checked out on Headphone.com showed a flatter response across the spectrum than any other model available. I don't know.
It's accurate, and I always check mixes with these. There are no near-field or mid-field monitors that have the resolving power of a quality pair of headphones, paired with an adequate amplifier of course. Plus not having to worry about modes from the room, is a good reality check. But stereo imaging must can only be checked with monitors.
These are also very comfortable to wear, with the self-adjusting headband. The fabric that surrounds your ears is a big factor with this.
Great 'phones for the price.