Received this yesterday:
http://www.backcountry.com/backcountry-merino-150-base-shirt-long-sleeve-mens
Price was attractive: $43.45 (reg. $79). Shirt appears well made, nice flat seams, decent athletic fit. 6.8 oz in size small. 1/4 zip LS merino base layers like this are my preference for most conditions I hike in.
I think I'll like the thumbholes, although I haven't had a shirt with them before. The zippered chest pocket I could certainly do without. The collar is a bit snug when zipped up all the way, and has a stiff interfacing that is odd–maybe it will soften after a wash or two.
Backcountry's merino never seems quite as soft as others, but still okay for me against bare skin.
I wouldn't have paid full price, but I'm happy with it for the price I did pay.

