I've only had a few hours to burn these in, but so far I am extremely impressed. As of now I have the FiiO E6 amp to drive them, and it pushes them better than I expected. Being that these are 250 Ohm there aren't many portable amps that can do these cans justice. They frequency range is what I'm most impressed with 5Hz-35000Hz. They provide bass if you want it, and it is pretty clean and tight. The mids are very enjoyable, and I believe the highs to be pretty good too. Overall these headphones are great, especially for their value.