How would you compare them to the m50x? If I recall correctly you had them before?
It's like a refined M50. I had a colleague who had one, that I listened to a bit and remember it had hard hitting bass but did sound a bit metallic in the mids and was also a bit too aggressive to my liking in the treble. Also quite uncomfortable.
The MSR7s look much nicer, come with 3 cables and have very comfortable pads. Build wise they feel rather solid, doesn't feel plasticky and mine doesn't have any creaks or things of that kind, the sliders have solid and nice adjustment detents.
Sound wise the MSR7 follow the typical Audio-Technica house sound, but they are quite balanced sounding which I quite like. Less bass heavy than the M50s, but they do slam when the music calls for it, but this is definitely not a bass head can. The mids are very smooth and quite present like my CKR9 in ears, so is a bit forward sounding, but very detailed in the mids (not up there with my HE-500 which is probably one of the best headphones in that respect). The treble isn't rough, but quite present and a bit of spike in the 9-10Khz range to give it the feeling of having a bit of air. No nasties in the sound signature due to colourations caused by the driver housings which immediately gives it a seal of approval compared to other closed headphones I've listened to. I've spent a bit of time with the Momentum M2 in Dion-Wired the other day and definitely prefer the MSR7 to those. These aren't as good as my Audio-Technica CKR9 in ear monitors or up there with the Sennheiser HD600/650, but will be fantastic for the office. Isolation is quite good, but I get the idea that these will leak a bit of sound due to some vents in the housing so will see how that goes. Anyway, I highly recommend these!
If you want to see this headphone shine, put on "While my guitar gently weeps" by Regina Spektor.