Is this stuff any good vs. silk long underwear? DD is freezing walking back from the library near midnight in the Midwest. Her birthday is coming up in a few weeks, and the new Uniqlo store is somewhat close. She's not coming home for Thanksgiving, and I don't want a popsicle for Christmas! Heattech is less than half the cost of silk, so I could buy her twice as much. . .

I'd appreciate any feedback on Uniqlo items and their quality!