It's all relative to the noise in the room the person is using the headphones.
Even if there is about 10-20 db noise (EDIT: more than normal) in that room, the closed back headphone will sound a lot better.
Also the closed back is much more flexible, and can be used anywhere, everywhere. I could probably use the lcd-3 about a couple of hours a week. However the closed back version would never leave my head.
Edited by Marleybob217 - 10/13/12 at 3:41pm