I have the Chama and Labrodor. I wear these for early season, only. I personally do not find merino wool to be warm.
For me the Chama is a little scrathcy, but I can live with it. It also has stretch out considerably since purchase. Like others have stated, the Labrodor sweather is pretty light.
I really do like both items, esp early season. I wore the Chama for 7 days straight (no showers), and the garmet did not stink at all.
If you are looking for warmth, I recommand a medium weight polartec top (patagonia, marmot, ll bean make good ones), for base layer with Sitka Traverse over top. Very warm combo.
chris <><