Before I look a long airplane trip to Asia, my husband recommended that I purchase these Sennheiser headphones.  I insisted that I didn't need them, and he argued right back that I wouldn't be regret buying them.  Ahem.  Yes, sometimes husbands can be right.The over-the-ear design ensures that most sounds -- even the annoying whine of jet engines -- are minimized.  I had no idea how loud airplanes were until I put these on instead of the airline supplied ear buds and my better, but still inadequate, iPod buds.  I listened to my iPod and the in-flight movies for hours before my ears tired.  The sound quality is much better in a quiet environment than in a noisy one since, yes, some noise gets through.  For those who listen to music in an office or in a college dorm, the fact that they don't leak much sound is a huge plus.  My only complaint is that they don't fold or collapse to take up less space in my briefcase.These make a great gift for the traveler or just for someone who wants lightweight, comfortable headphones. 

Question: How about the quality?
Answer: The sound quality is much better