I have found that when I'm listening to the W3 phones, I listen with my iPod turned WAY down (maybe 15% volume). That's not that unusual for me, especially with sensitive phones. What's weird about it is that the music sounds loud to my ears -- I'm always tempted to turn it down a little more. Then I take one of the headphones out, and with ambient noise (in a quiet office environment) to compare to, the headphone that's still in sounds ridiculously quiet. I've never had this experience with any other phones, in fact, I often used that trick of removing one phone and listening to ambient to make sure that I"m not cranking my headphones too much. With the Westone 3, I find that I can be listening at an incredibly quiet volume, but because of the isolation and the detail, my ears interpret that music as very loud. Does this ring a bell with anyone else?
The Desire to listen @ lower volume levels because you don't feel the need to make up for the lack of dynamics with extra Volume.
They make you want to listen more.