So this one doesn't exactly have a brand name and its not one of the best, super great ones out there, but it was one of my first ones and it's still the one I use when we do FTX's and for PT in the morning.
You sacrifice some of the compression that other binders give, and it doesn't make you totally flat, just depending on what you have, but the comfort of it for physical activity far exceeds any other binder I've worn. It lets me keep my flexibility a bit more, and its not as hot because of the material.
It feels kind of like a sports bra that compresses more. If you're set on being 100% flat, it's not the one to go for. But if you're willing to sacrifice a little, it's definitely one I would suggest at least trying out.
The bad part is that I don't think you'll be able to find a physical location to try it on, but for me, I took the measurements and corresponded and it fit pretty well.
There are some comments at the bottom too that talk about the sizing, and they helped me pick the right one. https://www.amazon.com/gp/product/B00VGGIMZM/ref=oh_aui_detailpage_o09_s00?ie=UTF8&th=1&psc=1
This is just my experience with this particular binder, there may be a better one out there. Let us all know if you find one!