Regardless, if you opt to switch out of Scizor with Sylveon (which is probably the best bet unless the situation calls for you to be able to make an alternate play), it can mean a free U-Turn and momentum sweep from the opponent.
Even though Ferrothorn's not really that strong, the one in the video IS Life Orbed and is using STAB Power Whip, and also lands a critical against Pangoro. While not as noteworthy as Sylveon because there weren't any other multipliers, it still only did a little over half of Pangoro's HP.
At the current rate though, it looks more like Sylveon could counter Lati@s (unless Psychic ends up resisting Fairy) thanks to STAB SE and tanking abilities, and it could be a nice special tank with some Outrage blocking utilities. If nothing else, it looks like a decent enough special tank that doesn't act as set up bait like Blissey does.
"Religion keeps pressing B when we try to evolve." - pirategeorge" [3DS FC: 1934-0673-9848 (Pentao)]
Something doesn't seem right here. Just ran a calc of LO Modest 252 SpA Politoed Hydro Pump in rain vs 252hp/252SpD Calm Umreon - 50.5 - 59.39%
A crit should kill it.
Assuming Sylveon gets something like 130hp/110SpD or vice versa, I really don't see why people think she's 20x better than Umbreon. Something is definitely off in the video. Either that's something like lol water gun/water pulse, or the ivs/evs/natures are skewed into Sylveons favor. Or maybe Sylveon has a hidden ability or something, idk. Let's not forget this is GF, the people who think Rash is a good nature for Raikou.
tl:dr don't get excited just yet.
Somebody on Smogon confirmed that it was indeed a Hydro Pump Crit. However, they are arguing about crits being nerfed(a non crit did about 40%, Crit slightly above 60%, I think ?). Considering we know that Pokemon Amie will heighten crit chances, this doesn't seem unlikely.
Also debating whether or not Rain itself might be nerfed. :P