Bought these headphones mainly because of the logic7 decoder which is quite something, previously this system was only available in top notch amplifiers or in Range Rovers oddly enough; offering exceptional 7 channel sound. It does this by utilising Individual Virtual Acoustics (IVA) which processes the sound and presents the channels in such a way that it fools your brain into thinking that its coming from different dirctions. There is a far better explanation of this on the website.
Try it out with a movie that uses a lot of directional sounds such as The Matrix (the foyer scene) or any film with helicopters in !!!
In practice, the sound quality was absolutely exceptional when played with TV/DVDs/CDs and was able to handle walking around the house with no loss in quality that you can get with some other wireless/bluetooth devices.
Of course you don't have to use logic 7, theres also prologic and stereo decoders too, but who would when you have logic 7!!
They're also very comfortable, with an auto adjusting headband they don't slip off as you walk around.
The battery life is excellent, easily coping with a couple of movies and more; its very easy to keep them topped up as they charge when you place them back in the cradle.
In todays world of wireless this and wireless that, its easy to find 2 devices that interfere with each others signals; the AKG easily copes with this, with a convenient channel selector button on the headphones themselves.
Perhaps the only real disadvantage of this system is that it is on the pricey side, so you would have to be a complete audio-obsessive to get them.