Been wearing this a lot now and it’s a great item.
I have found that:
Dry + cold in the single figures I need a t-shirt (cotton t-shirt if just walking the dog!) or baselayer (poly-propylene if active) underneath for medium activity, fine on its own for high activity levels - need to throw something over it if stopping for an extended period of time though.
Warmer (early double figures) it is fine on its own up to medium activity levels but to warm for more than that.
Fine on its own in the rain with the temp in double figures
Not tried it in the rain in single figures yet with a base layer or without but I will.
Amazing in the wind, really good at blocking it
Imo it could do with some extra padding in the kidney area and when the wind is ‘right’ it can come in the side zips a bit
But Overall very happy with it, and performs well but it is not a one solution (on its own) for all situations imo. Still very pleased with it though.