I've tried to understand what the plant is since I first seen it. It is the Pokeweed in Poke Sallet, but I've never tried to eat it.
I have found the berries to be a real hassle as they stain your clothing horribly. The roots of these are really good for breaking up clay soil, so I don't find them to much. I only remove the plant from places where people could brush against them.
When they mature, they get huge. I've found them to be useful for bulk when making mulch.