These headphones sound very good and the convenience of wireless is a real plus. I like headphones but the cord can be annoying, especially when it catches on something. With these cordless headphones, that annoyance is gone, replaced by an occasional amazement at how nice it is to be cordless and how well they work. They can play surprisingly convincing rock or classical music at higher volumes (though I usually listen at low-to-mid volume).I connect to an iPod (through a Jabra bluetooth adapter) and a Motorola phone, which works very well. The links are easy to establish or restart and I have experienced almost no interference or dropping-out of the signal. Using an adapter means you cannot control the iPod with the S9 buttons but that is a minor nuisance (though it would be nice if a new iPod had that capability). The S9 does not play stereo directly from a Macintosh computer currently but Apple's new operating system (Leopard) is rumored to provide that capability. The rechargeable battery in the S9 last many hours; the first charge lasted only about 3 hours, subsequent charges have lasted 5 hours or so.I have only one reservation and one wish: although they are comfortable, they do eventually hurt after many hours of non-stop wearing and I wish they were more sound-isolating (in-ear).