The Garmin Vector 3 is one of two CPT Cycling recommended power meters, if you want power measurement to easily swap between multiple road or track bikes (the other being the Favero Assioma). The Vector "S" single sided power measurement is a more budget friendly option that is more reliable than most crank based single sided power meters. This is a great option to get you started on training with power. Even though the left pedal power measurement doubled will more than likley not be the same total power displyed as a dual sided power meter; a consistently reading single sided power meter will still give you a relevant indication of your training progress.
The dual sided Vector 3 offers power mesurement on both pedals, as well as pedalling efficiency measurements such as; torque effectivness, pedal smoothness and Garmin cycling dynamics, which identifies your peak power phase and how far inside or outside your power is being transfered onto the pedal, known as platform centre offset (PCO). These metrics help your coach to either identify effective pedalling technique or diagnose potential bike position issues.
