I own the HD600's, and they have better defined transient response than Grado RS-2's which I auditioned, probably because of less resonance. I also found the Grado's shaded too much toward the bass. Sennheisers win easy on comfort, but the 600's need a good partnering headphone amp if the sound is not to become fatiguing with their more difficult load. For the record, even driven with my quite capable Musical Fidelity X-Cans v.2 amp, I am ultimately still not satisfied that the 600's are as tonally nuetral as I would ideally want, but there may be nothing in the price range (or even at all?) that is. Headphones are a very personal choice, though, since everyone's ears and head (physically speaking) are different, so you really must audition some for yourself.
