These have the same excellent Ibex quality as the short sleeve base layers exhibit. I have also the heavier weight Ibex which can be a regular shirt as well as a base layer. These are a bit thin for that, but for a light super fast drying base layer they are perfect. On sizing, the Large of these is a little snug on me. The Ibex heavier weight ones, the size M is larger than this one's size L. In short these clearly are designed for a very snug fit. That is fine for a base layer, but you should know it in advance.
I backpacked from hut to hut on the entire Kepler Track in New Zealand wearing my wonderful Woolies 220 crew over a sleeveless Woolies 150 crew. My rain jacket and down jacket were too warm to wear while hiking at 4,000 ft. Simply wearing the Woolies 220 was as near perfect as it could be! I've purchased 4 of these crew tops, size small and wish there were more colors!