I read the manual as I was wondering what was best suited for my Golf R in the snow.
I didn't find in the manual what ESC Sport specifically meant, but from driving around in the different modes, I found ESC Sport to be way better for managing slides when I'm turning onto a road and the car isn't turning because I don't have traction with the hard turn plus ESC cuts me out of the picture.
I haven't bothered with the complete shut down of ESC (hold for 3 seconds in the Golf R).
Was glad to get some info on what ESC Sport does exactly, much preferred on slush and icy roads where I need to blip the throttle to get the car to actually turn rather than understeer.