After weeks of reading forums and reviews I couldn't decide between the Sony 1000X and the Sennheiser M2w so I got both to try. After hours of going back and forth between the two I finally decided which ones are going back. I have to agree with all the reviews about how the Sony has the best ANC around. Miles away from the Sennheisers. In terms of comfort I would say they are very close, with a possible slight edge for the Sony as the cups are slightly roomier. Where things become interesting is in the sound quality department. The Sony have a really good sound quality, as all the reviews and posts on thousands of forums can attest. But in my opinion (a complete rookie in terms of headphone sound quality reviewer) the Sennheisers are noticeably better. The soundstage on the M2w seems wider and the overall resolution throughout the spectrum is definitely better.
So, after shedding a few tears for letting go the Sony with all its bells and whistles, I am now really happy with my new pair of Sennheiser.