Dianawrote a review of Patagonia Capilene 3 Midweight Bottoms - Women's on November 3, 2015
Familiarity: I've used it several times
Fit: True to size
I will admit, when I first tried these on, I worried that they might slide down too much (as other mentioned in their reviews, and my roommate said hers were sliding off her butt), and I was somehow hoping they would be so much more soft. Negative first impressions aside, I kept them because I loved the color, and I was hoping for a great experience with a good base layer. I'm glad I did.
My friend and I just returned from a week in Iceland, where I wore this base layer almost every day. It was perfect! Kept me warm, didn't stink (didn't launder them for over a week), and I did not have a single problem with them sliding down. Perhaps that's because this is a base layer, that is meant to have something on top (which might help keep it in place?). I was glad to have the low waist, so there wasn't bulk around the waist, and I don't recall any thoughts of "my pants are sliding down." Another reviewer mentioned loose legs... definitely not a problem for those of us with thicker/athletic (or not)/muscular legs.
I highly recommend these.