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I'd say Omega Ruby and Alpha Sapphire. The DexNav is much easier to use than PokeRadar which can be a pain to chain on. Those are really the only differences in shiny hunting between the two games.
Now if you meant the original Ruby and Sapphire then X and Y would be easier. RSE have no way at all to increase your odds.
There's no way to catch shinies easier in R/S. XY is far easier as there: Chain Fishing and utilizing the poke radar (the chain thing is most frustrating as if you break the chain, the odd will revert back)