The MSR7 is back on special again at Takealot R2399. I owned a HD600 and and DT880. I have M70x, but tried out M50 and M40's. As Scubadude mentioned, the major difference is obviously, the Audiotechnica's as discussed here are closed back, the HD600 is open back, the DT880 is semi-closed (it's open, not sure why they call it semi closed). The HD 600 I think has an imdedance of 300 ohm, the DT880 in SA is usually 250 ohm, the MSR7 is 35 ohms. Only the MSR7 is really suitable for portable devices. The main thing to remember is that the aim is to listen to Music, not compare sound.