If this has been done I apologize.
This isn't a question of which legendaries are your favorites, but rather which regional set of legendaries is best overall. I'm curious.
Personally I lean toward the Unova Legendaries. Second place would probably be Sinnoh or Alola, probably an edge to Alola because the Lake Trio seems redundant within itself. I'm a bit of a Legendary nut so I do end up not considering Kanto, Johto or Kalos just because there are fewer and I don't prefer any of those legendaries over ones from other Gens.