Since I have never had stock, I cannot compare LOS to it regarding call quality. But I somehow remember @tdm saying the telephony bits were taken 1:1 from stock, so maybe there really should not be much of a difference ... All I can say is I'm happy with the few phone calls I make. Yes, sometimes I adjust the volume during a call, but no idea if the Pro1 is to "blame" in those cases, or whether it is my partner's phone.
That said, I am probably the wrong person to ask, really. I have accepted the fact that reliability and audio quality in telephony reached its peak around the time of the