I've had bad experiences with bluetooth. The first bluetooth dongle I bought used a chipset that is known to be faulty. I never got that one to work at all. My brother has a bluetooth dongle that I've used in the past that works flawlessly. The one I have at the moment works ok, but it's far from flawless.
There may be a way to get better results, but it could also be that the bluetooth device you're using, be it built-in or via USB, may be less than perfect.