Just put these on and they're thick, sturdy-seeming leggings. My main issue is the size. The M/L is a good 1-2 inches shorter than a pair of size "L" I purchased of another brand, but even more importantly, they are very, very tight. The packaging says m/l fits 145-165lbs. I cannot imagine this! I am 5'6" and weigh 132, and the waist band is a bit too tight on me - enough to be a bit uncomfortable - and I found them harder than usual to pull on. (More tight like control tops than snug & comfy like the leggings I prefer.)
UPDATE:
Although I see many others have stated that these run small :-/ I figured I should update my post since I took another look and discovered that the ones I was sent were mislabeled on the package...the tag on the actual read S/M even though the external label said M/L. So to be fair, the larger size might have fit me. Maybe!