I write an application that uses bluetooth serial links. We use a variety of radios like http://serialio.com/products/Bluetooth/BlueSnap/BlueSnapAAA.php among others.
The data rate is not much better than a dialup modem so the lesson is that while its grand for cell phone headsets and listening to some mp3 player you don't want to use BT when lag would be detrimental.
Does anybody know how much delay there is in bluetooth transmission systems? I have an electronic drum kit that routes to a sound board and then I listen in on wired head phones to get the full mix. How much time loss would there be if I used a bluetooth transmitter and bluetooth headphones instead? Would I hear everything with a slight delay?