[schotter]

After looking into Bluetooth and Noise-Cancelling headphones for my travels, I had to realize that the tradeoffs in sound quality are too big so I am looking at compact, nice sounding closed designs now.
 
My emphasis is on:
-Natural to spacious / 'sound-stagey' sound presentation
-Portability (folded in a carry-on bag)
-Maximum passive isolation
 
These cans would have to fit in a bag and provide somewhat usable shielding from my (plane or airport) environment.
When having arrived at my destination, they would need to be sufficiently natural and involving sounding to work with compressed to uncompressed files through a MacBook Pro (no headphone amp) or Ipad/Iphone.
 
Now, I read great things about the Senns and they do look nice indeed, but they are not really foldable which is almost a deal-breaker for me. At the other hand, the earcups seem to be smaller than the foldable NADs.
 
So I am wondering
-how they compare footprint/size wise
-how different they sound
-how their passive isolation compares
 
Has anyone listened to and handled them side-by-side? I see the Momentums around in shops but did not get my hands on the NADs yet.
 
thanks for input!