Disclaimer: I'm not much of an experienced reviewer so I apologize in advance for any misuse of terms. I also wanted to say that I have not done any other mods than expanding the headband.
A couple months ago I bought $60 headphones. I didn't really know about the brand very well -- I just recognized the name AKG from the Quincy Jones line and saw that they were 50% off. What were these mystery headphones we speak of? Why, none other than the k518LE, which is essentially the k81DJ.
Now that I've read more Head-Fi, I'm familiar with the AKG brand name and as more and more time goes on, I'm glad that I picked these. I do spend a good chunk of time with other headphones but I'm glad to always have these to fall back on. They're a bit small (for me), the leather pads get really uncomfortable, but I can sacrifice that for the great sound these provide.
Accessories:
These came with a small carrying pouch that I lost and a 1/4" adapter I never use (though I plan on buying a better amp sometime soon). Pretty much standard fare for a pair of circumaurals so there's not much to say here.
Build:
The build is simply put, solid. It's compact and really portable and yet it still feels like it can take a little bit of damage (a little). I'm really being nitpicky here, but the wire gets tangled too easily and I don't have the time nor experience to recable it. On a side note, the paint's chiping D:
Comfort/Isolation:
These isolate pretty well - so well in fact that I can serperate myself from what's going on around me (on second thought that might not be the best thing). In terms of comfort, it's a little bit more unpleasant. I have a larger head and it is a bit of a tight fit. I have left these overnight hanging over a textbook and that has helped with this tightness problem a lot though it can get a bit uncomfortable. On another note (as stated earlier), the leather pads can really get warm and a bit uncomfortable - I intend on ordering HD25 pads in the near future. (Sorry for focusing so much on the negatives - I can't emphasize enough that these are good but I find it kinda hard to describe without repeating myself).
Sound:
If you get the other three behind you, this is where these headphones really start to pay off. The sound is a bit on the bassy side but then again, they're DJ headphones not studio monitors, so what do you expect? There's a reasonable amount of balance though EQ can help in this area. The k518's respond well to EQ but regardless, they're good for listening straight up - they deliver the fun signature without going overboard and taking you into Beats land.
Value:
At the current price, I can't think of a better on ear headphone (assuming CAL! is not on sale at time of reading). It offers punchy bass with reasonably good overall sound with a few caveats. I highly recommend them.
I am running through a Bravo V2 with GE tube and they sound heavenly.