Neighbour wears bamboo base layers and socks and things and swears by them. She, of course, is one of those girl thingies and so that might, but shouldn't, colour her judgement.
In general, from the reviews I have read online, there isn't a bad word about them apart from cost and prejudice.
Mind, all base layers are moderately expensive for what they are. Be interesting to see if you get pestered by small furry creatures when you wear them.