I have a couple of Stubbert baselayers and am thinking of UnderArmour next for next winter, not that there is anything wrong with Stubbert, I have other UnderArmour tshirts and love them.
I have used alot of different base layers and Under Armour are far and away the best ones. They keep their shape and the "cold gear" range for winter keeps you lovely and warm...They're tough wearing too (I've used the same two for American Football for the last 3 years).