These are not noise cancelling, nor are they noise isolating. Meaning, in my office where I use them, I can still generally hear if something is going on around me provided the volume is reasonable. From what people around me say, there is almost no perceptible noise leaking out when I listen. They are the most comfortable over the ear headphones I have ever worn (compared to Shure, Beyerdynamic, Grado, Sony, mostly). The sound is nice and fun to listen to, doesn't tire me out after a 2-3 hours, but I find the bass to be difficult to find all the notes in and distorted, though there is plenty of it. Human vocals sound really, really warm to my ears.
Overall, I was happy to buy them for $65, for $50+s/h they are unlikely to be a disappointment.