In reply to MtnGeekUK:
I've got the rab alpine pull on, and it's fantastic. I get very hot and sweaty when walking, and coldish when stopping, due to the wind.
I wear mine in spring/ summer over the top of a t-shirt, vest or even a baselayer, when walking and even when going up steep gradients with a moderately heavy rucksack it's ideal. It keeps the wind off and allows you to keep cool. I also took it up snowdon with me a year or two ago, in the blistering heat, and when we stopped in the saddle near Garnedd Ugain, the wind started to give me the chills. On came the alpine pull on, and I was good to go. Even yesterday when wild camping, I had a baselayer, the alpine pull on, and my outer shell, and I was warm all night, without having to reach for any other layers.
The pockets double as vents, and the hood fit's over your helmet if you're that way inclined. It's not waterproof I don't think, but that's not what it's supposed to do.
I imagine the alpine jacket is more or less the same, just with a full zip.
One thing, is that I was amazed how thin it is and flimsy it felt, I don't think it would be very resistant to abrasion at all, but as a windstopper on the hills, I can't think of anything better. On the plus side it packs to about the size of a large tangerine.