I’ve got one that I use for running and cycling.
The cadence sensor stays on my road bike though.
The virtual training partner is a great feature, but mostly for road training rides and running.
Much of the time when I’m mtb-ing I don’t even bother with the heart rate strap and just use the unit to track where I’ve been.
(So I can bore the wife with metres climbed, etc when I get home!)
As above, don’t get the Garmin bar mount though.
It’s 10 quid for a piece of branded rubber. Go to a DIY store and get a small length of foam pipe insulation instead. Works just the same but for pennies.