Karen wrote a review of Black Diamond Couloir Harness on July 3, 2014
Familiarity: I've put it through the wringer
I spend a good deal of time on extended back-country trips so I've wound up using this harness for rappelling, rock and ice climbing, glacier travel, and moving on fixed lines. Once again, I love this harness.
As others have said: the size and weight are awesome and it's super easy to put on and take off so you don't have to fumble about when you're wearing large boots, crampons, or anything else on your feet. I'm also impressed by how comfortable it is, even when weighted, considering how minimalist it is.
As for sizing, I didn't have any problems at all. I wear size 6 in women's pants (an XS/S sport climbing harness) so I went for the S/M, figuring I would need more room for layering. Even when I'm just in base layers it fits me so that I have a few extra inches that I could tighten it, and when I'm dressed for warmth I have plenty tail to safely double back.