Having lived with these headphones for some months now, using them both for recreational listening, and for some more detailed mixing work I feel able to give some considered feedback.
Firstly, lets get any possible negatives out of the way. Buyers need to know that these are open back, and with that comes a great deal of spill, both in and out of the headphones. Sitting on the bus and using them to listen to music is very much not recommended ... but that's not what these are for.
Secondly, the build quality - whilst they've held up perfectly well over the time I've had them, they do feel somewhat flimsy. I'm careful with my equipment, and I think any user who uses a throw them-into-the-bottom-of-a-bag policy will end up regretting it.
Lastly amongst possible negatives are the slightly odd lengths of lead that come with it. One is rather short, and the other rather long. I've taken to using the long one as an 'extender' as needed, but usually use the shorter one. This works for me, but could be an issue depending on sitting position, placement of headphone amp/port etc.
The positives are obvious though: A detailed, clean, transparent sound, with none of the inflated bass found with closed headphones. This might take some getting used to (for those accustomed to earbuds, or closed back headphones).
They are very 'light', meaning physically they are easy to wear for long periods without neck fatigue.
Despite my initial fears about their durability/strength, they still happily 'clamp' my head, and are nicely adjustable (including the pads at the top). Some users appear to 'mod' these headphones with sponge and gaffa tape to make a 'band' at the top, but I've not found that necessary or desirable.
The price is excellent. Even if just being used for occasional mix-checking, at this price they deserve a place in the studio!
For recreational listening (which I'd recommend, in order to get used to their sound), they have proved excellent. I've enjoyed many styles of music, and continue to be impressed by their detail and lack of colour.
Overall - thoroughly recommended for the price, as long as you know what you are buying.