I have mild POTS that is made way worse with exercise, and I've been slowly incorporating compression clothing into my wardrobe for a couple months, on my cardiologist's recommendation. The first time I wore these with some compression socks, I felt like I'd almost instantly regained the exercise ability I lost to POTS (as long as I leave them on for a while after exercise, too). I'm already planning for when I can buy my next pair, or maybe I'll try the leggings. I love how long they are too. Mine have an 11" inseam, so they go just an inch or two above my kneecaps, and they actually don't ride up!

Some fit details: I grabbed the recommended size for my height and weight (XL, 5'6"/200 lbs) and I think they're probably the right size; the compression feels like what I'd expect from this grade. I saw some people in the comments saying they had to size down, and while they're not as tight near the abdomen, that's both normal for me with pants (especially midrise) and makes them pretty comfortable.

That being said, I'm also bigger around the hips/thighs than anywhere else, so I guess maybe if you're more lean through the legs you might need to size down? For reference, I usually need curvy sized jeans and wide-calf socks.