Power Meters / Powermeters (SRM, Powertap, Quarq, Ergomo, Vector, Stages, power2max, P2M, 4iii, InPower, Cinch)

They're both rather nice. Like the Power2Maxes, they just work. One threw a bit of a wobbly once, which was resolved simply by changing the battery. Other than that, all good, despite some very wet rides. I've no way of validating the numbers, but they seem broadly consistent with the data from the other devices.