Ibex Men's Woolies Crew

Great Base Layer!
Fits snuggly, but not as tight as compression. Excellent base layer, and wicks moisture fairly well. Ibex products (which are a bit pricey) are top-notch, and this is no exception.

The best baselayer for me
I've really enjoyed using merino wool for my baselayers and light midlayers for a little over a year now, and Ibex's woolies line are my favorites (at least the tops, the woolies bottoms currently are made with a too tight waistband even sizing up, while other ibex bottoms fit perfectly for me in medium). Due to the particular weave of these garments, they fit my form better, without feeling restrictive, and this helps me feel warmer, as the fabric remains in contact with my skin. This also helps the fabric dry off as there is no excess of fabric to hang away from your skin, and your body warmth more efficiently evaporates the moisture. I am 6' tall with a 6' 4" wingspan tip to tip, 160 lbs. , and with many manufacturers' size medium and large, the sleeve length is too short, but with Ibex, a medium fits me great. So it will depend upon your body type for how well Ibex garments fit you, but for me, their sizing is ideal. The woolies line feels very soft, and very breathable and comfortable. I would also recommend the short sleeve version of this shirt. If the garment (as with merino in general) feels itchy at all when first trying it on, a washing will make it feel softer.

Great base layer for cold weather aerobic activity
I use this as a base layer, underneath either a windbreaker or a long-sleeve t-shirt, for running in cool to cold weather. I am very happy with it. I like merino wool base layers primarily because they don't pick up sweat odor and can be worn a few times between washings (a nice feature when wearing for running twice a day every day). Note when I say "fits true to size" that the product description says it is "form-fitting." I am 5'10, 145 lbs, 38-inch chest, 32 sleeve, stereotypical "runner build" (large end of "small" on size chart), I bought a small, and it fits me basically the way it fits the model pictured (i.e., tight like the typical Under Armour "compression" fit). I have not found this to be itchy at all. Although the product description includes "moisture wicking," I don't find this (nor any other merino wool) base layer to actually keep me dry during intense running; however, it still keeps me sufficiently warm even when working up a sweat. I find synthetic base layers (polyester or polypropylene) to keep me more dry than this, but I still find this to be at least as warm if not warmer (and again, for me, not stinking of sweat is the key feature). My only question or doubt is the durability. I've only had it for a couple weeks, and it's so thin that I just can't help but fear that I'll rip it when I'm taking it off (again, it's pretty tight). It is still in good condition and shows no wear, but I just can't help but wonder how something so thin and "delicate feeling" will hold up over time. It comes with a lifetime warranty from the manufacturer, so I'm not too worried about it.