I like when main casts are more equal, and aren't following a single character more intensely than the rest, but both Ruby Rose and Twilight Sparkle hold those positions in their respective shows.
That naturally gives them a rather unfair advantage over other characters in the respective main casts of their shows as far as best/favorite characters go.
Because of that, I try to bring them down and see them equally with the rest. Sometimes I just exclude them mentally from polls and such because I know that 99% of the time they'll win.
For RWBY, that means Ruby. I won't use her position as the lead in the main cast as a positive towards her. I weigh her with the rest otherwise though, in such a case I still put Yang up as best/favorite character. Pyrrha for best side.
Ruby's cool though. Can't deny that. At least she doesn't have an impostor running around pretending to be her.
Yet.