I purchased these leggings with the intention of including them in my everyday wear rotation. They are a high-waisted, flattering flare, with lots of support, so would also be suitable for low-impact workouts, Pilates and yoga. I am normally between a size 10-12 in bottoms, depending on brand, etc., and I ordered a medium, and they fit well.
Personally, these leggings are slightly long on my 5"3 stature, but with shoes, fit perfectly. For me, the fit is not super snug, but that is a compromise for me due to normally landing in between sizes in bottoms (large glutes/quads and small waist). But if you prefer a tighter fit, I recommend sizing down.
The fabric quality is great with proper care; cold wash, air-dry, and irregular shaving (with fabric shaver) is what I find keeps them looking their best.