I've heard great things about Koss headphones but never got to try any. Are they really as good as people say?
I've had several of them.
The sound quality is quite good, compared to other headphones in that price range. They've got a lively and warm bass, making them perfect for rock, metal or electronic music. But they can also handle classical music. One of the cons is that they don't isolate very well. The sound leaks to the outside. They are also quite bad at blocking sounds from the outside. That is of course expected, because they do not enclose the ear like other headphones.
They are very light and sit well on your head, making them suitable for outdoor use and working out. Some people say they look ugly, but I don't care about the esthetics that much.
Oh, and they also come with a (limited) lifetime warranty, which is convenient. That means that if the headphones stop working, you just go to the store and get a new pair. Being priced at $30, I recommend these to everyone with a tight budget.