This is more of an informational note than full review. These type of leggings are used for all sorts of sports of which I don't use them for and can't speak to their usefulness for those purposes. I bought mine for running daily 5Ks followed by another 5K cool down walk -- literally ha ha.
I'm 5'6", not skinny, not fat, not muscular, and on the higher end of the "normal" BMI weight range. The medium size fits me perfectly -- this is my usual size for UA fitted and compression clothes. It's snug but does not strangle and I'm not begging to get out of them when I return from my routine. They are comfortable as far as compression tights can be.
The interior is fleece lined. I have other pairs of "cold gear" tights that are not lined but work just as well, but it does add to the comfort I think. I wear these in temps between 30-45 (not including any windchill factor). Even with a 25 windchill they keep me warm. My usual routine is an hour long, but only 25-30 min of that is running. The rest is walking which I'm not generating as much body heat. I think that says a lot about these leggings.
My only "beef" with these -- or any other compression leggings -- is that they are too long for my short legs, but probably not an issue for 99% of the population. I try to buy 3/4 leggings but they are a rare bird for men in a winter design. But despite the length the excess doesn't get in the way since I wear jogger pants over them.
Finally, I would note these seem to be intended as a base layer and not to be worn solo. The crotch area is "breathable" and a bit see though. So at a minimum you need to wear shorts over these.