Fantastic buy
These earphones have proven to be nothing but great for my listening experience, my working experience, and my hearing. No longer do I need to crank up the volume on crummy headphones to blast over top of the chaos inside a subway car, nor do I need to choose between music and a screaming baby or earplugs on a jetliner. The answer is simple; earplugs that become earphones. That's what these earphones are. My work productivity has improved due to better focus and a near total lack of minor distraction in an otherwise noisy working environment.

These also stay solidly in place when riding a bicycle or performing gymnastic moves. And best of all, the level of sound quality is so good that I can hear very subtle sounds even beyond the music, such as the occasional glitch in a computer's DAC unit (mainly when there's no actual sound being played).

I might just buy another pair, and I've already bought a pack of replacement foams. Those foams are great but they do get kind of nasty after a few weeks.

Very satisfied
Includes a variety of ear pieces so you can custom fit to your ears - even mix & match to get just the right "sound seal". Took them on the plane and could easily hear movies I was not able to hear with other phones. Nice carrying case included. Satisfied with the comfort and very satisfied with the performance.

Great value and sound
These earphones do the trick...the sound is great, and with the foam earplugs on, they keep out most (but not all) of outside sound. I wear these every morning on a commuter train, and they do a great job of delivering solid, deep sound from my iPod and keeping most of the ambient noise out. They are comfortable to wear for long periods of time, and the sound quality is better than other earphones I've had -- and certainly noticeably better than the standard iPod earbuds.

not perfect
First, these are not "noise cancelling", they are "sound isolating". That just means that the shape of the earphone attempts to block outside noise from getting into your ear along with the music.
I would say they are so-so at this. In an airplane, plenty of jet noise still gets in. Too much I would say. But they are probably better than nothing.

I like the shures because the "over the ear" design helps hold them in place while running or walking.

But the problem I am having with my year and a half old pair is: the insulation over the wires on both left and right sides has cracked at the point where the wire tightly curves around the back of the ear. This quickly frayed the wires and caused the earphone to begin to short out. This is of course unacceptable.

I have taped both sides and this worked for awhile but now one side is shorting out again while I am out on a 5 day trip. When I get home I will attempt to twist the frayed wires back together and retape them.

I don't know how much money one has to spend just to get music into one's ears and keep unwanted noise out. Obviously, way more than the music player itself and more than these shures cost.

shure not a great buy
the case is not in perfect condition a inside piece is missing. Get any answer from the reseller