I've had a fair experience with Bluetooth devices, including headsets, mice, and keyboards. At home, I am now using the Apple Bluetooth keyboard and mouse, and I am quite happy with them.

Recently, I thought I would look at getting a Bluetooth headphone, especially since the advanced audio profile (A2DP) seems to be getting more widespread, and OS X Leopard finally added support for it. It is just so appealing to go cordless.

So I ordered the Motorola MOTOROKR S9, which had pretty good reviews, and I connected it to my MacBook Pro. Here are the major issues I encountered:

• Even when no music is playing, there is a constant background noise. If you adjust the volume optimally and play pop music, you may not notice it so much, but this pretty much kills classical music.
• Interferences, which translate with pops and cracks, come up every few seconds or tens of seconds. I tried distances between the headphone and the computer of maybe two to then feet, with the same result.
  
• Background noise and interferences aside, the sound quality is metallic and full of artifacts which remind me of the first mp3 encoders back in the 90s. I guess that this may be due to the use of the low complexity SBC codec instead of decent compression on the wire.
• Using the headphone or headset along with a Bluetooth mouse simply doesn't work: the mouse will stop to a crawl.
• I got a complete OS crash (kernel panic) in the OS X A2DP driver. This actually happened after my headset was already shipped back.

The above I think fully justifies my sending the S9 back to Amazon. There are also smaller issues:

• I got into situations where no sound would come out at all when playing from iTunes, and I simply couldn't get things back to work without pairing the device again.
• I couldn't get Skype to use the headset microphone as input, but the high-quality A2DP as output.
• As a headset, the sound only comes out on the left side.

In short I am utterly disappointed because I thought that by now the technology would be ready, and it turns out that there is a lot going on for the S9:

• It really looks cool and is almost invisible from the front
• The sound quality of the earbuds themselves seems decent
  
• It is comfortable and lightweight
• As a headset connected to an iPhone, it seemed to work quite well
  

Hopefully the manufacturers will soon figure out how to really make this work. As it is today, I simply think that it is not useable, certainly not with a Mac.