Craft are a well known name when it comes to base layers and for a reason. The Warm Crewneck base layer is no exception from their excellent product line and it is a reason more to love the brand.
The 3D-Knit constuction (hollow fibers and body mapped comfort zones) of the material (61% Polyamide, 35% Polyester, 4% Elasthane) which is very lightweight and soft, keeps you worm without overheating. It is quite stretchy, without loosing its shape, next to skin, as it should be, following the curves of your body whether they are muscles or oversize belly.
The only issue with the fit was that size L, the size I usually wear for other Craft tops / 188cm height, 102cm chest, was quite long, something like a very short dress. I tried Medium, but it was only a 3-5cm shorter while being a bit tighter at the chest, so I went for the Large. In my opinion this is not a problem since I wear my base layers inside my bibs.
I have used the Craft Warm Crewneck base layer with a WINDSTOPPER non-fleeced jersey in temperatures between 8-15°C and it was enough to keep me warm and dry. In temperatures between 0-10°C I prefer to use it with a winter jacket and nothing more. If you plan to go below zero degrees, I would recommend adding another insulating layer between the base layer and the jacket.
Pros: Warm, wicks moisture extremely well keeping you as dry as possible, dries up quickly, does not loose its shape.
Cons: None really, except being very long.