Summary: These headphones initially worked great: fit well, good sound. But after a couple of months of use, the sweat from running waterlogged the speakers, even though these headphones were marketed as sweat & water resistant. The speakers still work, but the sound is very muted and poor quality. I would NOT recommend these headphones for any activity involving moderate to heavy sweating.
Summary: Let me start out by saying I am a fan of Sennheiser products. I love the HD-280's and several of their microphones are great. This particular product is crap. Yeah, they sound good, but they WILL NOT STAY IN YOUR EARS. I'm halfway through mowing my lawn, and came inside specifically to write this review...they are that bad. It's like someone designed them to jump out. Look elsewhere. Yikes.
Summary: I had these headphones for a couple of years before I finally gave up on them, or I suppose they gave up on me. The sound is noticeably better than the standard iPod headphones, but the iPod volume had to get turned up. The looks are a bit odd at first but pretty soon you don't care. I found they fit well but after extended use their shape would hurt my hear. They're slightly adjustable vertically for different ear shapes.
Summary: These are possibly the most disappointing headphones i've ever had (and i've bought a lot of headphones). I was really excited when i saw sennheiser has a sport headphone (and green is my favorite color!), since i've generally been impressed with sennheiser in the past. These things did not live up to the reputation for a few reasons: 1) they sound OK, at best, in a quiet room, without moving anywhere, but when you're in a noisy gym or running outside, or even just...
Summary: Definitely a mistake picking these up. Audio quality is good for the price, but the earbuds WILL NOT stay in my ears. I have determined that this has to do with the fact that I have a pronounced Tragus. If you're perplexed right now search for it on wikipedia. It's the flap of cartilage that hangs over the opening of your ear. If yours is large it will prevent the earbuds from properly fitting in your ear canal and I suggest you find a different pair of headphones.
Summary: I loved these headphones from the first time I put them on. Cord is really lightweight...doesn't bounce too much when running and ear buds didn't budge. The 5 cent cord clip that was included should automatically come with every set of headphones on the market. Keeps the cord from tugging on the ear buds. Sound was great....had to play with the settings on my iPod, but got that sorted out and haven't looked back. Great sound and fit for the value.