The M40X headsets have some pretty good pros:
• they have fairly large drivers for good bass response.
• They are closed back. This helps in holding off sound leaking.
• The soung above standard and pretty flat being an entry-level studio headphone.
( Something I should mention here is this is a studio centric headphones and not entertainment centric. So this would not have the type of sound an music and multimedia focused headphones like those from jbl and sony. But the great thing about the M40X is that it can deliver a great music listening experience.)
Now comming to cons. There are a few I should mention:
• The comfort level is pretty low in coparison to other headphones in the price range
• The sound is pretty flat but the highs ar a bit more which is abscent in the next model that is the M50X.
Conclusion:
These are a great pair of studio headphones if your just starting out as a music producer or trying to create your home studio and have a tight budget. But If you have some flexibility in the budget I would recommend your go for the M50X. It would deliver better results in the long run.