RNG has been good with me with regard to shinies. Definitely has not been with moves, I'm lucky if I get a 2/3 stat move. The most useful shiny I've pulled has by far been Rock Star. In rift, starting with RS, dash back to do a Ringlet Spike, inflict bleed, then tap at the enemy to get permanent bleed through the MA- and substitute in the next fighter with three stacks of barrier. This is insanely helpful in Rift, especially when paired with Overclocked whose barrier instantly reflects damage. I haven't developed Feathered Edges yet, but want to try it with her as well. Recently pulled a second shiny RS which will allow for the same tactic when attacking another node.