Pros: Very nice bass
Cons: Blah (so far)
I've used these for the past week. They have excellent bass extension but are very deficient in the upper mid, and treble range. I have not tried them with a proper headphone amp since the manufacturer claims they are designed specifically for portable devices (as the average impedance indicates). However using my iPod's bottom connections to a Philips portable DVD player and docking device, offers a substantial improvement. This leads me to believe they will sound at their best through a portable amp, and should prove to be very conservative on battery life. I don't foresee an amp solving the problem these earphones have with high frequencies though. If you don't mind tweaking your iPod to squeeze out the treble (because these are quite boring if you don't), the good news is they are comfortable to wear for over an hour at a time. I do start to feel pressure points and irritation after very long but they tend to subside. Very stealthy, and a good value if you prefer smooth bass extension over musical accuracy. I'll try to add my impression after I use an amp. Fingers crossed.