Earlier quoted context omitted.
Generally quite well. Pairing means your devices know to look for eachother, and the bitrate of music streaming over Bluetooth combined with the low range means you'll need some unrealistic congestion before things really start to fail.
unrealistic congestion before things really start to fail. aka public transit...
There are some BT devices that have poor antenna designs and underpowered transcievers, where the proximity of other humans — or even your own body — can significantly attenuate the signal. But this isn't a problem with the spec itself, and there's plenty of devices that have shown it's possible to do it right.