Pros: Excellent sound, hardly any leakage, don't require to be amped, coiled cable, low price
Cons: Uncomfortable, require a lot of burn in for best sound
It seemed these were the perfect headphones which met my expectations perfectly when i first got them, great sound, not too muddy, decent bass response without being too boomy or out of control, don't require to be amped (not even on my $30 logitech computer speakers) hardly any sound leakage, some passive noise cancelling... they seemed perfect! too good to be true. After i wore them for about a minute i already started to notice excessive discomfort these are without a doubt the most uncomfortable headphones i've ever worn, whoever has said something positive about the comfort for these probably hasn't worn them for more than 5 minutes, where do i begin? oh yeah they have a REALLY tight clamp, especially at the bottom of the ear cups under my ears i've had these for a week and have been stretching them over a box for about 34 to 43 hours but they still feel horrible, the speakers inside the headphones sticks out and rubs against my ears and it's really annoying, i tried stuffing cotton balls under the ear cups to seperate them but the sound quality got really tinny and horrible. then there's the headband, there's almost no padding on the headband and when i take them off my head hurts where the headband was, i've tried adjusting them and it just makes it worse. The sound quality of these headphones are great and probably the best i have/will hear in any closed headphone for such a good price, and that's why it's so hard for me to return them due to such discomfort, guess i'll never find the right headphones. 
Now there are some mixed opinions for the comfort on these as there always will be as different people have different shaped heads and are more/less sensitive to comfort so i would reccomend trying these on in a store for around 10 minutes and make an honest judgement about the comfort, some people will be okay with them but for me they're torture to my head.
Also could you guys please reccomend me a pair of closed headphones the most similar to the M50s around the same price range that are actually comfortable, and next to no sound leakage, i'm really picky about sound leakage.
- Thanks.
While I don't find my M50's as uncomfortable as you do, I do find them slightly uncomfortable. A headphone with good sound and a similar price range (though a little warmer than the M50's but not by much) and quite good comfort is the Sony MDR-ZX700 / MDR-7510. The clamping force isn't quite as high, they are lighter than the M50's and they are easy to drive - and you still get studio monitor sound. You should be able to find them to try out pretty easily I'd imagine, Sony being such a major brand.