Pros: Will NEVER break, mould to your ears, very comfy, awesome bass, crisp sound quality.
Cons: Discomfort after 2 to 2 1/2 hours, cable length too short, no headband padding, some may dislike the snug fit.
I got the Sony MDR XB300 headphones for my 13th birthday, and they were great. I was (and still am) at boarding school, and these phones have handled constant dropping, sharing and leaving about over the years with ease. Though I was no audiophile back then, I noticed that after a year the sound quality had significantly increased; the bass was less sloppy and the mids and trebles were very crisp- the only way I can describe this is that when listening to a drum track the hi hats and snares were very clear and the toms and bass drum filled my ears with a smooth bass.
Now, I'm not saying that these are accurate headphones, god knows they're not, but they are just really nice to use. For example, when I would sit down for a pc gaming session, I wouldn't be thinking "this is a shame because I'm gonna have to stop playing in about 2 hours because of the heat on my ears". I would think "god these gunshots sound cool!" or "I can't wait to hear that spaceship/soundtrack again!".
When I got these phones, I was very pleased with their comfort, durability and sound quality. Recently at my school there's been an outbreak of Beats by Dr. Dre (which are complete and utter *****), and unfortunately for those who have bought those treacherous things, they all say that they prefer the bass on my MDR XB300s. Which I bought for literally $150 (£100) less. Please, do not buy Beats.
However, 4 years on, 18 years old and looking towards a music production course at university, I've come to realise the two faults of the XB300s; cable length and discomfort. The cable length really isn't a huge issue for me, as I play various instruments which require me to move all over my home studio so I use extensions, but when I'm sitting down at my desk and working or gaming I often wish the cable was just that little bit longer so I could lean back in my chair or sit a bit farther away.
The more prominent problem, though, is the ear discomfort. If you're gonna use these headphones for an hour to two hours, you're going to have no problem whatsoever; the super-thick leatherette cushions are SO soft on your ears, they are almost comforting to wear. However, if you're planning on wearing these for longer than 2 hours at a time, the top of your head is going to become irritated by the lack of padding (it's just plastic) and your ears are going to BOIL. This may be because I have rather a large head and thick hair, but seeing as these cushions are so thick, I think this problem will apply to most people.
If you're willing to forgive the long-term discomfort issue, these headphones are absolutely fantastic. No, you're not going to get top quality audio, because you're only paying about $50 (£30), but I have recommended these headphones to friends of mine who do hi-fi work, need instrument headphones and dj, and I keep these faithful phones with me at all times.