Hi Sandy.
All of the scopes you have mentioned are the same scope, so no comparison is needed. These ED80's all come from the same factory but get labelled with different names: 'Orion, Saxon, Skywatcher, etc', and get painted different colours.
All have the same Crayford Focuser too
The ONLY ED80 in this quality range that is not from the same factory is the 'Celestron 80ED'., which has a few quirks that many owners of them don't like eg: the dewshield falls of easily.
The only difference in the ones you name is the mount.