Mediocre at best and that's coming from someone with very limited experience with compression/workout/man-leggings. Thin material, so they'd probably be good for warm weather. The material is significantly thinner than my Jockey brand Rapid Cool boxer briefs. Just sitting on the end of the bed after putting them on, I could see my skin on my knee. Very little compression. Was like wearing something, but nothing at the same time, if that makes sense. It's not that they weren't tight against my skin, it was just that subtle of a "compression".
For those still looking to buy and are interested in sizing info. I wear 34x32 jeans and have average thighs and calves. I bought a large and they fit just fine.