I bought these headphones randomly when I lost my other (more expensive) pair. The were inexpensive and looked good so I bought them to tide me over until I got another paid of the ones I had lost. That was almost a year ago. When I first plugged the headphones in and chose the right ear size the sound quality was unbelievable. Deep base lines and crisp treble, I have recommended these to my friends and they have been equally amazed at the quality. Yeah, you might be able to get a paid of Bose or something that are better, but I'll keep the $100 I save and buy some more tunes.
As for isolation, lets just say on more than one occasion I have not heard my phone ringing right next to me while I'm at work.
With all the garbage headphones out there that charge a lot and deliver a little, Coby has set the standard as far as I'm concerned.