I am overall quite pleased with these headphones. The sound quality is excellent. I've not had any problems with interference, background hiss or anything of that nature.Battery life has been excellent. I have not actually ran them all the way down to see just how long they'll last, but I use them to listen to music at work for the better part of 8 hours a day and they haven't failed me yet.The only reason I would not give them 5 stars is that they can be a little uncomfortable after prolonged use. I'm not really a big fan of this "sport" style of headphone, and probably wouldn't have tried these if I hadn't gotten them on clearance. But, I found that after experimenting a little I was able to get them situated to feel pretty comfortable, even wearing them the better part of a workday.