I usually wouldn't look for a base layer in this spendy price range but I need a little retail therapy one day and came across this softwool top from The North Face. I got a $40 Patagonia base layer at the same time, and I gotta tell you - this one was worth twice the price. It has a super flattering cut with curvy, slimming seams. The wool is not itchy and adds a good amount of warmth; I find I wear it by itself as a regular shirt as often as a base layer.
The surf blue is true to color shown on the site and is super cute. It also has long sleeves with thumb loops which I happen to love.
For sizing: if anything, it fits a little large as do most things from The North Face. I'm usually a medium and sometimes a large in tops, especially long sleeved tops because I have long arms. I got a medium in this top and it fits me perfectly. It's long enough in the arms that the thumb holes are usable, and it's long enough in the back to tuck in or just leave hanging.
Get it, you'll love it. Or get it for someone as a gift and they'll love you.