Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Headphones perform well

I purchased the Koss Sportapro headphones to use with my IPod Nano. I was surprised with the overall sound quality. The sound responsiveness is very good. The main reason I did not rate them a 5 is they are not quite as comfortable as I would like. I use them while I exercise, and I find that I have to adjust them for comfort long before I am done.