There is no difference! You will still have to download Uplay either way. The only thing to remember is that you have to purchase DLC on the launcher you own the base game on.

Originally posted by indio68: thanks..i already have an uplaya ccount cuz i'm playing the free week end...i wanna ask if i had to re download the whole 70+ giga again..thanks

You will have to reinstall the game. There is an update tomorrow that is basically reinstalling the whole game + Void Edge content.