These certainly fit snug, I am 165 (5'10") and use a size medium.Great baselayer when heading out on the mountain or even backyard with the kids. wicks away moisture very well but sometimes I find that it feels a bit damp after a day of hard skiing (although you never notice the dampness). Same issue when using it for running it does not seem to dry as fast as some of my other tech T's. The bonus is that you really do not have that damp feeling that some of these products have when using them.
Overall decent baselayer, I am not sure about the anti microbial layer as I find they do get a case of the stinks if they sit around in my laundry bin for a few day (similar products that have anti microbials i have used did not have this same prob)