These headphones simply blew away my previous set of sport headphones (Sony MDR-A35G). The only areas where the Sony's are better are comfort in the ear and the fact that the Sony's are fold-able. The sound quality of the Sennheisers is excellent for the job that they do as a sports headphone. Sound reproduction is excellent. You can hear the singer inhaling and exhaling, you can hear the pick plucking acoustic guitar strings and everything else in astounding clarity. One might say that they are lacking a little in the the bass department. But when compared to other sports headphones, these Sennheisers excel. I see people complain about the comfort, but you just have to get used to them. Here are some areas where they can use some improvement: there should be some way to manage the cord when not in use so I'm using an Etymotic cord winder; the color of them is atrocious and I would love another option on the color.