[S/M] Shiny Charm!

[Fooni]

I prefer SOS, but sometimes MM. Few Pokemons are better off getting it through MM, Like Shiny Sableye.
Because Carbink is the only Pokemon that calls Sableye and Sableye only comes in once in awhile.
Basically any of the Pokemon that can only be called during SOS and are not of the evolution that you are hunting.
But yes, all other Pokemon's seemed to be easier for SOS for me.