they sound great i cannot listen to low quality files anymore because i can hear the difference.. build quality is also good and while plastic they dont seem like they will break anytime soon and i used to carry them in a knapsack. i like how i can use them with my phone, ipod laptop and computer but can also use them with my receiver amped with a 1/4 plug.
i'm a bit dissapointed that the pleather is starting to crack (this is common on all pleather pads on most headphones out there) but replacement pads are relatively inexpensive and considering i listened to them almost every day at work it was bound to happen. since they are closed headphones they can get a little hot after a few hours so i normally take them off for a few minutes to let my ears cool (however this is true with any closed headphones...thats the price you pay for soud isolation). again... not a fault in the least.
the cable is a bit long but its better to have that then a coiled cable (i really dislike coiled cables) and i just wrap up the excess in a little pile on the desk. the long cable does come in nice if you want to lean back in your chair while listening to music on the pc. you can take a nap without worrying about the cable stretching tight.
i pad about full retail price for mine. kind of an impulse buy. i could have saved $60 by going online. completely worth retail. a real steal if you get them for cheap.
as i said before... for the price you cant beat them.
as far as the 1% who dont like them.... most of them try to compare to higher end headphones and say they arent as good ($150 compared to $400 headphones or some dumb argument like that), complain about them being plastic (most headphones are plastic), complain about a so called lack of middle ranged response (and after having them for years i still havent noticed such a thing), complain about the long cable (but its not really a negative), complain about the pleather (but most headphones use pleather), complain they make your ears hot (but all closed headphones do) or that they do not fit the shape of their ears and are uncomfortable (we all have different shaped ears/heads so perhaps the m50 wasnt for them).
most of it is just bickering without any real sense. you see it alot on the internet.