I have a pair of Bamboo socks and the g/f has a 'boo base layer... my only gripe is that they seem to take ages to dry in comparison to my merino items.
But, I think Bamboo feels nicer
But, I think Bamboo feels nicer

What is the most common Welsh sheep then Harvetsman? Cumbria has the Herdwick and the swaledale too IIRC due to their truly tough character. Snowdonia is just as wet and wild so is there a sheep type for that area. The Plynlimon area is also pretty tough.
Bamboo is biggest con going. Far worse than cotton for any serious outdoor activity 'cos it soaks up wet like sponge and then takes a long long time to dry - so potentially dangerous if weather turns bad. Use some commonsense - how can any fabric recommended for babies diapers, bathrobes, towels etc. be any possible good for outdoor gear? No real evidence that its anti-microbial - just say-so of manufacturers. That goes for all the other claims about it - US FDC ruled it was illegal to make them.
I use merino socks - they don't stink - can wear them for days before they need a wash. The length of time it takes them to dry depends on thickness.
Not for the eco warrior members by the looks of it.
http://www.treehugger.com/sustainable-fashion/is-bamboo-clothing-truly-green.html
http://www.muchbetteradventures.com/news/view/109/bam-booo-is-bamboo-clothing-really-eco-friendly