This is what Rab say about it:
The Polartec® Classic 100 lining in the Vapour-rise Climb Jacket makes this the warmest garment in the Vapour-rise range. The Vapour-rise Climb Jacket is worn over a base layer as an effective 'soft shell' in all but the very worst of mountain weather. By balancing wind resistance, warmth and breathability the jacket creates a comfortable operating environment through a wide range of temperatures and activities and excels for mountain walking and mountaineering. Weight: 570g
- Pertex Equilibrium® with Polartec® Classic 100 lining.
- Shield water resistant treatment.
- Three zipped chest pockets.
- Drawcord hem and venting Velcro cuffs.
- Full length 2 way zip.
- Stretch Pertex Equilibrium® shoulder and arm panels.
- Wired peak hood zips into collar.
This is what I say about it:
It fits me well as a baselayer or, if it's sub-zero, over one. I've worn it in some good and some fairly foul weather, it has resisted driven rain and snow but at no time have I either overheated or chilled. It doesn't ride up at all even when at full arm-stretch, and it doesn't slide about under a pack. Others have commented on the length of the arms, and yes, they are longer than expected, but the Velcro closures at the wrists are gusseted, so you can form comfy thumb-loops with them or you can roll them up. The lined zip-away wired hood is surprisingly good and easy to deploy without taking off the jacket. The fabric is durable, the only weak point that I can see is the stitch-work - everything is single-stitched, which means that a pulled thread could result in a gaping seam (double-stitching would have been better and wouldn't have upped the weight by much). I like the pocket arrangement - very pack-friendly.