I wouldn’t recommend Rally XC if you ride a lot of gnarly terrain. I broke 2 pedals - given the ‘XC’ I do is most natural trails with some very tech climbing. Rock strikes may happen the odd time.
Furthermore, The PM was never consistent compared to even my smart trainer or my infocrank. It seems there can be a drift in the reading. Even if this can be collaborated mid-ride its enough for me not to trust it.
Finally, I had drop out issues but went away after garmin sent me a door battery door - this was when the pedals were fairly new and I always torque to spec.
For a ‘premium’ option PM - I’d just expect better. I’d go for a Segeyi or a crank based PM if you are intending to ride a lot of technical terrain or even borderline trail/enduro riding. But given how easily I broke 2 pedals - I’d imagine anyone MTBing would make a mistake within the next few years (especially considering it may be out of warranty by then) - and you’ll have to fork out 100+ euro for a new body yourself.
On a positive note - Garmin replaced both the pedals free of charge which is great.
For gravel riding / CX and tame XC its probably adequete.