Pros: Durability, appearance
Well first off, these headphones are bashed on way to much just for being 'Beats'. The studio's straight up suck and the solo's are beyond bad. These suckers take on quite a beating because of the 'sins of their forefathers'. Personally, the price wasn't as big of a deal with me since I got these for 300 new, but price is the main downfall of these guys. They are far from worth 400 dollars for their sound quality. You could find the same if not better sound quality in 250$ headphones.
However, these headphones make up for this quality in their build. I found this strange coming from Monster. I have dropped these puppies from 6ft+ several times, slammed the chord in between a car door several times, etc. Not even a scratch (which is strange since aluminum tends to scratch pretty easily from my experience). They also have a removable cable (quite common in higher end headphones) that can plug into either side. This is the most amazing headphone cable out there. It is long and built to last and doesn't tangle at all. The swivel cups are also pretty fun and cool but really don't add all that much overall.
Sound quality wise these are lacking for their price. They would be worth it at 250, maybe 300, however they lack the outstanding highs. They have great bass (it could be a little more punchy) and pretty good mids, but the highs aren't close to anything special. These headphones also don't differentiate instruments as much as IEMs but they do give songs a solid feel. Despite not having the best sound quality, these headphones really bring rap, hip-hop, electronic, dubstep, and even hard rock to life. (if you like classical or softer more detail oriented music I would go with sennheiser or Westone).
Overall these are good headphones, don't listen to the hype saying 'beats are terrible', they really aren't all that bad.