I had some Black Sheep gloves on my Christmas list, and took them to Sweden dog sled touring hut-to-hut for a week in February. With daytime still-air temperatures down to -36C, these were not the only handwear that I used - but they were the only ones that I could actually do something in, and they were incredibly warm for a single layer!
The best thing about these gloves is that they are very 'liveable' - they are relatively dextrous, tough and above all easy to slip off and on again; permanently attached with "idiot leashes", it was easy to slide a glove off for seconds to do bare-finger jobs (you do this a lot around camp, and harnessing the dogs!).
I'd choose these over any other glove I've used (including some pretty expensive climbing gloves) for anything in the backcountry.