I am comparing these headphones to other products people may be interested in.Shure SE110Apple Ear BudsSeinnheiser HD280sSony EX71Skullcandy Ink'dPros:More comfortable than ear buds or closed headsetsExtremely portableInexpensiveExcellent sound quality (recessed mids but excellent balance and richness for the most part)Can hear the outside worldCons:Can hear the outside world, and they can hear youReally need to be broken in for the sound quality to go from amazing to exquisiteOn their own, the PX 100 headphones are extremely comfortable, fit well, collapse for portability, and sound amazing. They are relatively inexpensive and have a beautiful warm, boomy sound that was absolutely shocking when I first put them on. They are the best sounding headphones I have that I can wear comfortably.These headphones have very similar sound quality to the HD280s but tend to make music more enjoyable. While the 280s are more analytical and balanced, the px 100s are more colorful and have more bass. They also do not highlight the highs so much that poor quality audio files are impossible to listen to. These headphones have half the impedance of the 280s which means you are getting richer sound in a more portable package for half the cost- with increased battery life on portables.SE110s are slightly clearer and allow individual instrumentation to be heard better, but their sound quality does not create a balance (favoring the highs) that makes music enjoyable. They are also not comfortable. Both are good for classical music but I think the PX 100s are better because of their warm sound and deep lows, which really brings crescendos to a climactic finish where SE110s always leave the listener feeling cheated out of the final hit.These have the same depth of bass response as the Sony 71s, but are more clear and are not as muddy in the mids and highs.They are about as clear in the highs as apple ear buds (they are better than most people want to think) but also allow for clear bass and do not sound tinny and like someone pushed the right side of an equalizer to max.The Ink'd ear buds are the closest in terms of overall sound to these and cost only a third of what the the PX 100s cost, but are less comfortable, do not stay in your ear, translate the sound of the cord, and only sometimes sound right (you have to have a perfect fit, which is nigh impossible)These are my favorite pair and I only put them away when I *must* be isolated from my environment. They have an amazingly rich, warm sound which adequately plays any music I can throw at it. The clarity in the upper range with older music can lend to the bass overpowering some music. It isn't as noticeable as it is when my Klipsch 2.1 system plays the same song.These are a no-brainer and I liked them more than the KSC75s, portapros, and bose triports I tried. 

Question: How is the sound?
Answer: go from amazing to exquisiteOn their own