First, these are amazingly comfortable--the cut is good. They are also very smooth to the touch , but not shiny at all, very matte. The seaming is good (it looks like the old-time seaming from the inside of Levi's). But as far as "tummy control"? Nope. These are just too giving. The stretch is excellent.
They are also very lightweight--not exactly thin in the material, but even my no-pantyline undies were ever so slightly visible. The pockets are pretty large. The iPhone 10 fit perfectly.
For the record, I'm 5'6", about 150lbs, and I ordered a Large. It's a bit bigish, but the stretch takes care of that, and frankly, a Medium would probably have been too tight.