I've picked it back up recently and let me tell you: Pixie Plate + Pixilate + Hyper Beam = woe to anything that is a Fighting, Dark, or Dragon type. My level 35 Sylveon took down a level 50 Haxorus in one blow and it didn't have a Pixie Plate yet.
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TsunamiBye
Hyper beam is always a bad idea. You give your opponent time to set-up and wreck you later. Your opponent will sacrifice a pawn to bring in a set-up sweeper to wreck poor Sylvie and her team. If you want the best kind, run with a moveset like this:
TsunamiBye
Bold nature with Leftovers Wish, Protect, Hyper Voice, filler move of what your team could use. Or check this link out: http://pokemondb.net/pokebase/167894/what-is-a-good-moveset-for-sylveon
I don't play Pokemon no more, but good times.