Summary: They effectively cancel noise only to a certain extent. In a classroom full of chatty people, it cancels most of the noise. However, walking down the sidewalk along a moderately busy street, or just walking anywhere on a very windy day, it doesn't work so well.
Pros: I am not very familiar with much variety of audio-related technology, but from my untrained perspective they are very good.
Cons: While the quality may be great, the bass isn't noteworthy. They're just fine for everyone however, unless you really care about heavier bass.
Summary: The ear-buds themselves have no insulation against the cord. When the volume knob knocks against your chest while walking the sound transfers through the cord and into the 'buds -- it's really obnoxious. The only way around this problem is to turn up the volume to drown it out; hence: not ideal for listening on the move.
Pros: Decent sound, long cord, carrying case, lightweight, self-volume control, fits in ear well.
Cons: The cord has terrible memory problems, it seems near impossible to straighten it out after coiling. Partly because it's in a single housing, instead of two, and partly because it is super light and just doesn't have weight to straighten itself out with.
Pros: Excellent quality on all levels... fits comfortably in the ear without the soreness that can come from other ear buds. I was surprised by the quality of the lows. I've listened to everything from Pandora to lossless audio and been very satisfied!
Cons: I've liked the noise canceling in my Shure ear buds better. These do a decent job but not as much as I would've liked. But for 50.00 I'm not complaining.
Pros: Absolutely wonder sound, big upgrade over OEM earbuds. Tight deep bass, very good meds and highs. These sound much, much better than the low cost Skullcandy earbuds and as good as the high end models.