In reply to Richardhobbs:
I’ve got a Nano Air Light, and an Alpkit Katabatic.
I also owned the previous version of the Nano, but sold it as it didn’t fit me. I also have an Arcteryx Atom LT.
I would say the Atom LT is the perfect winter midlayer. Whilst the Katabatic is excellent, it is a bulkier /warmer jacket. Great for standing around in but on the warm side. It’s almost like a light belay jacket, ie not a million miles away from a ME Fitzroy.
The Nano Air Hybrid is great, but doesn’t work super well on its own, not being windproof, apart from the front.
I have found a base layer, R1, hoody, atom and paramo to be a good combo when climbing.
If wearing a shell instead of the Paramo, I’ll swap the Atom for the Alpkit Katabatic.
This will all be backed up by a medium weight belay jacket.
HTH
Tom (who owns to many coats)