Pros: Sounds amazing, cost is nothing, quality is wonderful, value is ridiculous.
Cons: Somewhat uncomfortable for very long listening sessions, leaks noise like a sieve (not really a con, just something to be aware of).
This were my first "real" headphones and now I'm building a Mosfet Mini Max tube amplifier and DAC, buying parts, modding my headphones, etc. All in three short months. These will turn you into an audiophile.
The clarity from these are just wonderful. Rich, full mids, wonderful treble response (perhaps too wonderful...at times they can be very bright and tinny, but usually not) and a good low end too. This is, of course, pre-modification. With the drivers vented, new grills, new headband, custom wood cups, G Cushions and the driver cloth removed, these headphone dominate.
That's probably one of the coolest things about them, the amount of known mods! These are so much fun to play with, mine look nothing like they used to, sound totally amazing and are very comfortable.
My two cents? Get some cans from the Grado Prestige Series, modify the hell out of them and have fun listening to some amazing headphones for the price.