While I definitely still have issues with Bluetooth keyboards and mice, I have three pairs of bluetooth headphones (two of which are BT4, one is BT3) and they work great.
The only real problem is switching between devices is still much more annoying than it should be (I ought to be able to just select the device from the drop-down on the desired device).
The only real problem is switching between devices is still much more annoying than it should be (I ought to be able to just select the device from the drop-down on the desired device).