I'm 19 weeks into my second pregnancy now, so I'll try to update this after more time to change size.
In my job, I both stand for long periods and have to sit with my legs in a dependent position, and I'm already getting tired feet and have a righteous varicose vein. It receded completely after my first pregnancy, but now it's larger and in-charge-er than it ever was before. These provide so much relief and do an excellent job compressing my unwanted squiggly companion. They feel like they physically lift me up to be lighter on my feet as I walk.
As the other reviews say, they are some work to put on, but relative to what I expected, they're not THAT bad at my current size. The instructions are very helpful. We'll see how this changes with getting bigger. I did size up from what my measurements indicated, and I'm glad I did- these still seem to compress perfectly. They were a little long on the first wear, but after a wash and tumble dry, they're the perfect length. The waistband is secure, sits nice and high over the belly, and has some additional room that I think will accommodate a near-full term bump very well. It does create a little bit of back muffin top, but you know...pregnancy.
For reference, I'm 5'8", nonpregnant weight 148 lb, currently about 13 lb up with already a decent sized low-riding bump and some extra pregnancy body fat mainly in my back, legs and hips.