My initial want was to just see what my heart rate was doing during MTB rides, with a Polar chest strap selling for £50 I revisited the idea of a Cycplus M2 cycle computer instead, it offers more stats, tracks and syncs to Strava but has no guidance ability.
I've taken the plunge and ordered one with a HRM strap, one sensor (I initially took "dual sensor" as it being one sensor able to monitor cadence AND speed but each sensor can do either cadence or speed not both). I've brought a K Edge steerer tube / in front mount separately. I'll probably use the sensor as speed as if mounted to the crank / chain stay I can't see it staying put during MTBing which is a shame as I'd like to see cadence every so often.
Awaiting its arrival.
Any other users?