These are the third-most-expensive in-ear headphones I've ever bought. Not the most expensive, mark you. But they are, by quite a margin, the best-sounding ones I've had.
I am less of a fussy audiophile than I've been in the past (a young family will do that to you!), but I do still very much appreciate and recognise good sound when I hear it.
When they're fitted properly, the sound from these headphones is truly remarkable. Especially with simpler arrangements and vocals, the soundstage they produce is wonderful. I feel like I've had an extension inserted down the middle of my head and the soundstage goes well beyond my ears. Listening to something like The Man Comes Around by Johnny Cash, with its simple guitar and piano, you can hear all the beautiful resonance of the body of the guitar, every mute of the strings, and the full, rich timbre of his voice ringing out clearly over the top of it all. Choir pieces, like Down To The River from O Brother Where Art Thou, also sound gorgeous, with the whole ensemble audible. The crescendo, three-quarters of the way through Paolo Nutini's Candy is another great example, where you can truly hear the drummer working his way through the tom-toms and cymbals.
On rockier tracks, like Razorlight or Rage Against The Machine, they are less bassy than perhaps some fans of rock music would like, but there's plenty bass response (it goes surprisingly deep too). It's just that this response is part of a detailed, neutral overall sound.
Even on big band numbers like Big Bad Voodoo Daddy's Mr Pinstripe Suit the delineation of the different instruments is clear, and the track skips along superbly, underpinned by double bass and trombone lines that my £250 speakers on my hifi (coming through a Cyrus pre and power amp) simply don't reveal more than woolly glimpses of.
The fit is good, although you may be sorely disappointed with the sound if you don't take 10-15 minutes to experiment with all the sizes to make sure you've got the right one for your particular ear shape. If you don't fit them properly, the bass is practically non-existent. The Stay Hear fitments are great, and I'm confident they won't fall out when I'm running.
All in all, they're that rare breed of hi-fi equipment. Something that makes you hear all your favourite music all over again, because they're so revealing. For the money, they're very highly recommended.