I bought a merino wool shirt from First Lite this year (saw reviews in both Eastmans and Field & Stream). It's not cheap, but hoo-boy it is super comfortable. Kept me feeling dry on several days of 8-mile hikes and it's been durable through several washings.
I liked it so much, that I bought some in black (plus bottoms) to wear at work (police officer) and it has been fantastic. Can't rave enough about how it feels comfortable and really moves the sweat to help you feel dry and warm.
I used to wear various polypro, fleece, and other synthetics. Some were good, some were not, but none can compare to this First Lite stuff.
In all fairness, I've never tried the UA cold gear for a shirt, but do have pants and I think they're the best of the synthetics (but I'd still grab my wool first).