My expereince with both of Patagonia's Merino Wool and Capliene in the medium weight is that the Capliene dries out much faster. The wool is warmer, but that doesn't mean much when you have other clothing along for warmth.
This fast drying quality I find really important when I do a tough climb over a few miles before sunup and then stop to glass for an hour or two. That's where Capliene has it all over Merino Wool. E
I've got to partially disagree with you here, E. (which is only, of course, my experience vs yours). Although I will agree with you 100%, on that base layers should be thin as a rule, vary insulation layers for warmth instead.
While I agree that Capilene dries quicker than wool, I find that once I sweat it up and stop, I get so cold so quickly in the Capilene while it's drying that it often isn't practical to wear it alone while waiting for it to dry. When I used mostly Capilene, I'd often carry two layers and let the one I wore hiking in/up dry while glassing in the other. With wool, while it dries slower, I am warmer and more comfortable in it while it is drying, allowing me the time to wear it dry without chilling.
When I used Capilene, I'd bring changes of layers. With wool, I bring only the top I wear, even for week long trips.
I've got a drawer full of Capilene, and I'm contemplating selling much of it off, as I'm pretty well sold on wool or blends as of today.
