I've had something in that fabric for a couple of years and its been fine for me.
The potential weakness might be breathability, that might depend how much you sweat etc - its been entirely fine for me.
Hydrostatic head more than high enough to be waterproof. The hood/other bits may or may not be limiting in terms of what weather you'd happily use it in - you'd need to check actual jackets, and their fit, for that. Given Montane likely pretty good.
Durability in terms of abrasion or tearing - so a rucksack - should be rather good actually. Probably somewhat more so than the lightest event jackets actually. The face fabric seems to be ~microlight weight and thats known fairly tough.
The slight durability weakness is just that this sort of coating doesn't last for ever so there's a long term limit on its lifespan.
(note that the jacket is the old pertex shield, not pertex shield + which is a different coating and often rather lighter face fabrics.).