Summary: Replacement tips for all in-ear headphones are tedious to locate and are way overpriced then slapped with a shipping charge that makes them really overpriced. I'm just sayin'....
Pros: I did a frequency test on these and I was surprised..., no, shocked that the bass response was jaw dropping. Output was smooth and rich through the broad midrange, which was quite solid. Highs fell off pretty quickly at around 15,000KHZ. Still, a little equalizer adjustment and they perform like some in-ear phones for which I paid 10X more... literally. I'm glad that I had and assortment of ear-tips... see Cons below.
Cons: The tips that come with this unit are no good for me. The shaft of the tip is too short to fit deeply enough in my ear canal. It's the seal in the canal that gives the set a chance to develop a true bass response and isolate outside noise. I have many sets of competitor in-ear tips and replaced the original. Without these replacement tips, the sound was tinny and disappointing.
Pros: They aren't GREAT or anything. I noticed that I have to have the volume turned up *significantly* on my phone to achieve a sound level that is set lower on any other headphone.They also have just average bass but I suspect you will notice the sound quality is lower if you listen to music that has a lot of bass.
Summary: i got these for Christmas 2011, they where excelent out of the box. even compared to my Senns they are amazing, they sounded incredibly detailed next to my PortaPros and even my Senns. the soundstage isn't quite as good as i would like, but this is before burn-in. i'll give an update after burn-in in a post later.
Pros: amazing SQ, tight bass, very detailed
Cons: seems to get rather confused at the top end. lack of bass impact