Summary: didn't rate Noise Reduction because that's not what they're for. I use these to plug into my amp so I can play along with iTunes with my electric bass rather than blasting it loud and playing along with my acoustic. These really handle the lows and I like the overall sound and comfort of them.
Pros: fairly lightweight and comfortable. reproduce what I'm listening to really well. reasonably price too!
Summary: I was looking for a quality headset that delivered comfort and great sound and at a reasonable price. I found the HD518 to give me what I was looking for. PLUS, they were on sale which made them more appealing.
Pros: Great sound, very comfortable, fits around my ears well. They are also built well since I accidentally tripped over the cord and the headset fell on my tile floor with no damage. I was impressed.
Cons: They don't offer noise reduction but not complaining.
Summary: These headphones sounded incredible from the moment I put them on, and if there is truly a break-in period as some say, and they're only going to get warmer - I probably won't tell... since I can't imagine any better. These headphones make my more expensive Audioengine A2 speakers sound like a Fisher Price toy, so that's kinda of a bummer. I don't think I'm going to mind wearing these all day though. They're very breathable thanks to the open ear grill.
Pros: Comfy, Amazing, Sennheiser
Cons: Sound leak through grill on high volume - for home use
Summary: These headphones are great. After a good couple hours of breaking them in, they really are nice. They are on the larger side, so if that's a problem, I would note that, but for me they are fine. The sound is something else. All the highs are crisp, sharp, easily distinguishable sounds. The low range is also rather impressive. These definitely have the oomph you need to get what you want out of your music.
Pros: Great sound. Comfortable. Available at a reasonable price, worth the money.