I bought a pair of these in white in April, and they lasted me a good 4 or 5 months of solid useage. The sound quality from these is pretty good, although it does take a bit of getting used to if coming from regular earphones. The bass is powerful, and distortion (on heavier metal tracks) stays tight when it needs to be, and demonic when it has to be. It keeps unwanted sounds out very effectively, and is very hard for others around you to hear, even when at max volume.
My only gripe I have with these is that I have lost one of the squidgy earpieces for the only two sizes that fit my ears, and without replacements available, it renders them virtually useless. The holding on these pieces was very good for a while, but it eventually succumbed to wear-and-tear and they would occasionally fall off in my pocket. Although, I do put losing the pieces down to my own fault, so don't let it put you off too much.
Well worth it, especially for the price here! You won't regret this purchase, although you will never be able to go back to ordinary earphones, as I have recently discovered!