Summary: I've tried a much more expensive pair of earbuds, and I actually prefer these over those ones. These are very well reviewed, and apparently very good for the price (try to get them on sale, as with almost any headphones).
Pros: They're good. You're better off reading a serious review than reading what people have to say in these reviews. However, these seem to give surprisingly clear sound and a wide range of frequencies. The highs seem particularly nice.
Cons: Doesn't have an anti-tangle cable, and if the cable jiggles around, it seems to translate to more noise in my ears than what I'm used to.
Summary: I used some sennheiser headphones before and always liked the sound signature (warm and sweet/crisp) but a lot of they're headphones didn't fit my head. I was in the market for earbuds for rides on the bus and saw these on sale and payed $31 with tax and shipping. These IEM's are great because for $30 they have amazing highs, average mids and great but not overpowering bass.
Pros: detailed crisp sound with a bit of sibilance before burn in. Comfortable, very good build quality.Cheap ($25 on sale).
Cons: Vocals are a bit muddled and on the backburner. Lower mids are a little muddy. There is some sibilance before burning them in, my source also contributes to this because its very bright.