Pros:Durable, relatively inexpensive, very effective at sealing against external sounds.
Cons:Pretty uncomfortable, tonal balance and imaging are only average.
The Bottom Line: If you have to have sound-sealing headphones, these are an acceptable choice for the price.
As other reviewers have written, the HD-280s are probably some of the "sound sealingest" headphones you can find. I've worn ear protectors while shooting that let through more noise than these do. But the downside of this is that these cans really clamp down on your head. They can be hot and uncomfortable after just a few minutes of use.
Recommend this product?
I must have a small head, because the complaints voiced elsewhere about the HD-280s being sized for smaller heads didn't ring true for me. I'm able to expand the set quite a bit as I put them on and take them off, and it doesn't seem to unduly stress the headband.
Unlike with some other Sennheiser headphones, I don't think that you can replace the cord easily on the HD-280s. My HD-212 cord unplugs from the earpieces and I've replaced it once already (due to abuse on my part). Fortunately, the cord appears to be quite durable.
Unfortunately, the cord is also coiled, which is a big "no-no" in my book. Coiled cords serve no useful purpose for use in the home or while traveling.
Efficiency is about average and you really need a separate headphone amplifier to make these shine. They're just not a real good match for a portable media player without external amplification.
Tonal balance is not nearly as good as with the open Sennheisers. Even the bass sounds muffled to me. (These phones are intended more for studio and DJ use.) I also own a pair of HD-595s, which cost twice as much, and you would not even guess that both phones are from the same manufacturer. Imaging is also not particularly good, as the drivers are positioned almost directly across from your ear canal. You can compensate somewhat for this by tilting them back on your head.
Of my sealed headphones, which include the Ultrasone HFI 700s, the Sennheiser HD-212s, and the Sony V600s, I'd rate this a distant third, with the Ultrasones being the top performer. If you have to have sealed headphones, I'd suggest saving your money and buying the Ultrasones.