Pros: Fantastic sound for the price, mostly neutral but with a nice, warm midrange that's good for vocals
Cons: Will be a bit bass light for some, very heavy, exposed wiring on headband
These headphones are a great bargain for anyone wanting a very good monitoring headphone that delivers great SQ across the frequency spectrum.
This is not the most fun sounding headphone since it is designed for monitoring, so if you like your music with a decent bit of coloration, then you should look elsewhere.
That said, it is not completely neutral. It does have a somewhat warm midrange that makes it fantastic for listening to vocals. Overall, for the price you pay, these cans offer a decent amount of detail and an overall balanced sound that should please audiophiles who are on a budget. Bass is accurate and tight, but a bit on the light side. As others have said, they can be a bit sibilant on some recordings.
Impedance is 44 Ohms, but it is fairly easy to drive from a laptop or mobile devices/MP3 players.
The only niggles with this great pair of cans is that they are a bit heavy. That's not to say they're uncomfortable (they are fairly comfortable), but they have a good deal of mass. Overall they have a very sturdy build, but I didn't like the exposed wires above the earcups. Thought that was a bit of an oversight on Shure's part and could lead to damage if you're not careful. But if you treat your audio and tech toys with reverence and care (like I do), you should be fine.
After 2 years of using them, I would highly recommend these. They have a very good reputation both here and elsewhere online. For the money, you cannot beat the clean, detailed sound these offer.