Forgive me in advance for this review won't be focused too much on the sound.  From the little while that I was able to listen to these headphones, they sounded amazing.  They had a neutral tone and clarity.  They were certainly capable of putting the low end out there, and they worked well with my Cowon IAudio 9+ without an amplifier.  They were built like a brick outhouse, they'll turn heads when your wearing them out and about, and if you have a small enough head, they'll be highly comfortable.
 
Of course, that's only if you have a small enough head...
 
If you have a prominently sized cranium, you should probably steer clear.
 
For one, they might not even fit.  When I first put them on, I had to set the rods on the highest setting.  Doing so, I thought maybe I had lucked out, but that's only where the issues started.
 
After about 30 minutes of listening, I started to feel the effects of the clamping factor of the headphones where the bottom part of the earpad was making contact with my neck.  It wasn't much, but it was enough to notice, and if the pads themselves hadn't been as soft as they were, then who knows how much more intensified the discomfort would've been.
 
About 2 hours in, that tight clamping factor started to diminish, giving way to a fit that was less than secure when coupled with the headphones relatively massive weight.  On top of that, the middle of the headband started to press down into the top of my skull, skipping discomfort and going into pain territory.
 
I suppose I can't put fault on Master & Dynamic for the fit of their headphones.  They can't make a headphone that's suitable for everyone.  And I'd still recommend these to anyone with regular sized noggins.  Anyone else....well, make sure you hold on to the receipt.