Just so the first part of the review isn't negative, I'll write it in reverse. I love them. I've been using them mainly for music (prog-rock/rock/pop/dance/rap/rnb... varied taste ;) ). They're very light and comfortable on the head, the sound is well defined across the spectrum, although they have virtually no response below 40Hz. The audio is clear at low volume, and doesn't distort when I turn them up - I'm not sure of the top volume, but they go loud enough for me to want to rip them away from my ears without much noticeable distortion, or sounding too harsh. I haven't got any other good headphones to compare them to, but I can safely say they thrash my Bose Tri-Port earphones, and they give comparable sound to my ~£700 HiFi setup (Wharfedale Diamond 9.1, Cambridge Audio Azure 340A amp, CA DacMagic and mordaunt short alumni9 sub). They're plugged into the Tape output of the amplifier. Can't comment on battery life as I haven't listened for more than 3-4 hours at a time so far. They come with GP 600mAh 'AAA' batteries though, so it will be easy to upgrade them to some good duracell rechargeables.
The main complaint about them seems to be the placement of the volume/power buttons. This isnt really a problem at all - there is a row of three buttons and its easy to feel the ends of the row. The up volume is at the back or the row, the down at the front. simple as. I've only turned them off accidentally twice, and that was when I first used them.
The range is decent. my uni halls have lots of brick walls, but it still covers the whole flat. Between my room and the kitchen there is one room, the shower, the toilet and the cleaners cupboard, all with brick walls, and I get good reception in the kitchen. That's through 5 4" walls. (although at that range it cuts out if I put my hands over the cans)
Now to the first impressions. Pulled them out of the amazon box, and the whole thing was light as a feather, albeit a very nicely packaged feather. i realise the the headphones need to be light, but the base is also light, and to the touch, a bit plasticy. Despite feeling a bit cheap it does look the part, and its not exactly handled much once you're set it up. the main downside is you have to hold it to push the power button, otherwise you just push the whole thing backwards. The headphones are also light, but don't feel plasticy, are very flexible and feel well built. I don't think I'll be breaking them any time soon.
Upon first listening, they sounded very bad. Harsh treble and mids, and no bass to talk about, even with bass boost on, i gave them a chance to burn in though, and this was completely gone after about 30 minutes of listening. They're still improving a bit after I've had them a few days.
Overall I would give them 4.5/5 because of the base and having to hold it still when pushing the power button, but as 4.5 isn't an option, and I like them too much to give them 4... 5 it is.