UA gets a bad rap for being overpriced, but their gear works. As it says on their site, this is a great shirt as a base layer when the temp is below 55*.
I played this weekend on a sunny low wind 51* day. I started with this shirt, a fairly thin long sleeve polo and windshirt. By #3 I had dumped the windshirt and was more than warm enough the rest of the round.
It was nice to feel warm without a lot of layers or bulk.