With merino make sure you buy from a good company e.g. icebreaker or a few of the other top ones (cheaper brands are just not as good e.g. macpac feels far coarser to me).
Some people don't react well to merino (you can be allergic to it and some people still feel merino to be as prickly like non-merino wool) so I'd recommend getting one half and seeing if it suits you first.
If it suits you it's as good as most other baselayers, but it may also be worth looking at meco by Rab (and a few others) as the cocona should add wicking properties that wool lacks.