We are decidedly low tech and settle for one computer on our tandem. Seeing that we are both riding the same bike, going at the same speed and to same destination we feel no need to get more info.
Have not gotten involved with HRMs . . . our hearts beat, we ride. Quits beating? Hey we must be dead!
Still using a hardwired 'puter, a Planet Bike Protoge 9.0.