I have been using the AKG K 240 mk ll's for 4 months. What I like most about these headphones is how great they sound. Its truly amazing. I also have a pair of Sony MDR-V700DJ which are also nice headphones, but in comparison, don't perform like the K 240's. The sony's can get muddy towards the bottom end where the akg's stay nice and crisp. Its never a good idea to mix solely with headphones but these guy's will let you do a decent amount of work and not have to tweak too much when listening back through monitors (a handy tool when on the go). The other great thing about these headphones is they are shipped with an extra set of ear pads (the pair that are already on are like a velour, the other is like a soft pleather) and an extra cord (one is a straight cable the other is a spiral cable like a old school phone cord). It is really nice to get these extra options, especially when paying upwards to $200 for a pair of headphones. The only thing I didn't like about these headphones was how "cheap they felt." I say this with some hesitation because at first, I was disappointed (even worried that I had gotten a cheap knock off because I got them off ebay) about how light and thin they felt when compared to the sony's. Its a big difference. But after plugging them in and hearing how great they sounded and using them for hours, I realized that the "lightness" makes them the most comfortable pair of headphones I have ever worn. One more thing I should mention that really pleased me was the ear cup room. Its like your ears are completely surrounded but no pressure is pushing against them. Thats a big bonus because after hours of use with every other headphones I have used, including the Sony's, the parts of my ear that stick out the farthest (the middle area) will get sore.
If you use headphones on a regular basis, you can't afford not to get these. $200 is a lot of money but these were worth every penny. Infact, you might find a pair new on ebay for much less. I got mine in a package deal that, had I payed the street price for the mic and preamp I got, these would have been free. ($500 for a ART Digital Mpa Gold, Shure Sm-57 and these headphones). Check Ebay.

I might even buy another pair down the road just in case.