Being able to 1HKO is always good, sometimes you just don't have the resources to get that KO without your GX attack. I don't know why Rayquaza becoming a thing would be bad for a fairy card, and Zeraora is not going to be as good as people are hyping it up to be. Sylveon does have an easier setup than Ninetales, but in the later game Ninetales' ability is far more useful than Sylveon's attack, because your turn doesn't end when you use it. Sylveon KOing things without Choice Band does not really mean anything considering Ninetales can just search it out when you play it down.
Pardon, when I say that Rayquaza GX becoming a thing is bad for Alolan Ninetales, I meant specifically the GX attack. Ray GX/Zeraora GX runs no Ultra Beasts, so in a potentially Ray GX saturated format, you basically are running a GX Pokemon that doesn't have a GX attack. That can be fine because no one uses Zoroark GX's GX attack either, but I'm just saying it's a factor when compared to other Fairy Pokemon trying to fill an attacking role.
Right now my current take on Alolan Ninetales GX is that it's good for a stage 2 deck, but if you're stage 1 heavy, Sylveon GX is just as good if not better.
Here's the power play I imagine with Alolan Ninetales GX:
1. Open Beacon Alolan Vulpix and search for two of your Stage 2 Pokemon. Let's say 2 Gardevoir GX. This is IF you have Ultra Ball in hand to grab Alolan Ninetales GX as well. This will also work if you just open Gardy GX in your opening hand. Play Pokemon Fan Club to put 2 Ralts on the bench.
2. Evolve up into Alolan Ninetales GX and search for two Rare Candy, and make two Gardevoir GX just like that.
If you are T1 going second, you can potentially have 2 Gardevoir GX out by turn 2 of the game due to turn 1 beacon. Otherwise, you will have to wait until Turn 3 if you're going first. T1 set up, T2 beacon, T3 evolutions. This, however, is also the best case scenario for the deck. Odds are, you're going to Beacon for 1 Alolan Ninetales, 1 Gardevoir GX, and then use Alolan Ninetales' ability to find 1 rare candy and 1 nest ball to pop out your next basic to start setting up.
I recognize this power play, but at the same time with things like Professor's Letter gone, Alolan Ninetales cannot find energy. What's the point in T2/T3 double Gardevoir GX if you don't have any energy in hand to apply pressure after setting up? Sylveon GX can always set up a single Gardevoir GX after a Pokemon Fan Club, and I can take a DCE with the search and usually have 3 energy on my Gardevoir GX by turn 2 going second/turn 3 going first of the game.
Having to use Choice Band to OHKO DOES matter. That means that Alolan Ninetales GX is forced to expend one of its searches on a Choice Band whereas Sylveon GX never does in a Ray or UNGX match up. It also means that a Field Blower can stop you in your tracks trying to use Alolan Ninetales GX as a main attacker, because you can't guarantee the next Choice Band unless you're willing to evolve up a 2nd time and consume another bench slot just to find a choice band.
The point is, neither Sylveon GX nor Alolan Ninetales GX are perfect for the job. Depending on the deck, one will be better than the other.
Alolan Ninetales GX is specifically better in any deck that wants to search for Pokemon and items without needing to splash in an off-type energy, but if you're going Gardevoir GX + one of the two, I'm going to need playtesting results to prove to me that Alolan Ninetales GX is better than Sylveon GX in an upcoming format with no N and very little Judge. And as far as GX attacks are concerned, if Gardy does come back to steal the meta, then Plea GX sending away 2 of your opponent's Gardevoir GX is a game winning GX attack.
