Literally thrilled with these joggers. I'm solidly a size 12 across most brands, and the XS fit perfectly! I actually ordered the S (14-16) initially, assuming that if I wanted to be comfy and unrestricted I'd have to size up, even when buying loungewear – but nope, not with US! The XS is exactly what I wanted: nice high waist (fitted but stretchy), skimming through the thigh, loose at the knee/calf, and then a strong taper down to the ankle! They look very sleek while being ridiculously comfortable, and are surprisingly warm for such a lightweight fabric.
US was awesome about exchanging the first pair, too – they sent the new ones as soon as I sent off the return, and they came ultra-fast! Shipped on Thursday, received on Saturday. :)