I say you get the Shiny Charm in Omega Ruby. You have a greater variety of Pokemon to get in there. (Take it from someone who had the shiny charm in X). You can get amazing shinnies such as Ho-Oh and Reshiram easily with the shiny charm! There's also the Masuda Method, which can get you any breedable shiny you want! (With patience, of course)
Hope I helped! Happy shiny hunting!