Pros: Very pretty, does some new genres like indie rock well.
Cons: Fatiguing, Uncomfortable, Terrible bang for your buck
These cans were decent, back when they were just above 100 bucks. They've inflated to 160 and that's just ridiculous. There is better in this price range. The SRH840's for example on eBay for 120~ bucks new, does everything better than these cans. The M50's have really punchy bass, and extremely stringent highs, they're very loose in the low end, and their mids are recessed. That combination makes for a fatally tiring listening experience. The pads are pleather and terribly uncomfortable, whilst having an almost starchy texture to them. The headband clamps onto larger heads and lacks decent padding underneath. These phones are also terrible in regards to any soundstage at all, which means for gaming, these will be pretty terrible. They do some... SOME... new genres alright, but their extremely aggressive presentation makes these phones just hard to listen to. They also can't do lighter genres like Jazz and Classical due to their poor positoning. There are much much better monitors in this price range than these, the Shure SRH840 as I've said before totally outclass these headphones in all areas.
The Head-Fi vets are right, stay away, don't fall victim to the hype.