I haven’t used a Steady Betty, but I have friends who say it keeps things from stretching while pressing. I don’t press anything with a bias edge until it has been constrained by something else. For general pressing of blocks, I really, really like my wool,mat. I have never had such flat blocks and well pressed seams. I love mine so much I went into withdrawal last winter on a snowbird RV trip when I forgot it at home. I bought another one for the motorhome so that never happens again.