I kind of like both, but if I had to rely on one long-term, which would you go for?
Here are the vital stats of both for you to digest:
MDR-NC6:
Driver units: 38 mm, Neodymium
Max. power: 100 mW
Impedence (with power on): 20 ohms
(with power off): 65 ohms
Sensitivity: (with power on): 106 dB/mW
(with power off): 104 dB/mW
Frequency response: 30 Hz-15 kHz
Range of noise attenuation: 40-1500 Hz, more than 10 dB at 300 Hz
MDR-NC22:
Driver units: 13.5 mm, Neodymium
Max. power: 50 mW
Impedence (with power on): 20 ohms
(with power off): 8.5 ohms
Sensitivity: (with power on): 102 dB/mW
(with power off): 100 dB/mW
Frequency response: 8 Hz-22 kHz
Range of noise attenuation: 50-1500 Hz, more than 12 dB at 200 Hz
Of course, the annoying thing about the NC22's is the over-long 1.5 meter cord while my NC6's (after I desoldered the 1.5 meter cord on them) have a more remote-friendly cord (similar to the JE Version of these same units) taken from an old pair of MDR-EX71SL's and I kept the extension cord as an option.
Your opinions await, I am all ears, but my management recommends I go with the MDR-NC6 headphones despite the stats instead of IEM's to keep the hearing I have left.