I wear a 14 dress and got 2XL and it fits well. I’d say it’s more like medium hold than firm. Not a ton of “sucking you in” compression, but it definitely helps smooth you out. My only complaint is that the shoulders are a bit wide-set, I’ll have to figure something out. But for $8/9, it’s still a win. And I think this is the only body shaper with free returns.
Make sure you buy according to the measurement chart, Asian sizes are different than American sizes! You usually have to go up 2 or 3.