If you pay the right price for these headphones, they are totally worth it. I purchased them from the Apple store the other day, and paid nearly $70. Then I found them online for $30, with no tax and free shipping. At $70, I can't say that I'm fully satisfied. But at the $30 price point, these headphones are great! Long story short, I will be returning my headphones to Apple and keeping pair I have purchased online.
But enough of my shopping experience... The sound is pretty decent, compared to what I have found with over-the-ear headphones. And they ARE fully adjustable. The previous reviewer apparently didn't notice that you can easily bend and shape them to very comfortably fit your ear.
I also tried Philips ActionFit Earhook Sports Headset (SHQ3007), which are around the same price point. I much prefer the Sennheiser over them.
If you're a runner and you are looking for decent headphones at a good price, I would definitely recommend these.