So after seeing some of the UltraBeasts get their first scans, I gotta say, they are all very lackluster. Not a single one has an ability/attack that is game changing. I'll go over each card and the strength and weakness to each one.
Buzzwole GX: http://www.pokebeach.com/2017/08/buzzwole-gx-and-guzzlord-gx-revealed-at-worlds
Pros:
190 HP which is crucial for the big basics in the current meta with things like Gardevoir and Metagross around.
Jet Punch hits active and one bench for 30 each for one energy cost.
Knuckle Impact hits for 160 which can be buffed to 190 (All big basics) with a Choice Band and 210 (All Stage 1 GX's) with a Kukui+Band. Attack can be reset by Guzma/other switch methods.
Has synergy with Carbink BREAK, Registeel EX, Brooklet Hill and Scorched Earth.
Absorption GX has a massive 240 Damage cap un-buffed.
Cons:
Fighting Type. With only Darkrai as the primary fighting weakness, the Fighting typing doesn't favor Buzzwole moving forward. There isn't and Electric Type Pokemon that are announced that will hit the top of the Tier List (Raichu GX is a worse version of Darkrai EX, and we see how Darkrai EX is dropping on the Tier List), nor is there a Dark Type Pokemon that will show on the Tier List (we will talk about Guzzlord next). You could argue that it has good typing against Drampa GX and Silvally GX, but that's not enough to warrant the a Fighting Type to be good.
Weakness to Psychic<Garbodor GUR.
Retreat cost of 2. The reason why cards like Gardevoir GX can have a retreat of 2 and not be hurt by it, is because it plays DCE. Buzzwole GX however, doesn't want to play DCE, so that cost of two is now expensive. Not to mention it limits the searching ability to just Brooklet Hill and Ultra Ball.
Absorption GX is an expensive, early game attack only. With the attack lowering in power with every attack, 240/200/160/120/80/40, you can see that its GX attack is only useful within the first three prizes when dealing with decks like Fire or any Stage 1 GX deck and even then it's only useful in the first two prizes when dealing with Metagross and Gardevoir. With a cost of THREE Fighting energy, it's also extremely expensive early on.
Knuckle Impact is also too expensive. Having a cost of three Fighting energy hinders this card greatly. Has it been a Fighting and a DCE, that open the door up for this card to have an impact on the meta. But where is sits right now, you HAVE to pair it with Carbink BREAK for the energy acceleration. It also helps Gardevoir be closer to the OHKO range. Three energy on Garde+Choice band is a OHKO, or just 4 energy on Garde is an OHKO.
This is the most playable out of the UltraBeasts and it has too much going against it to be past Tier 3.
Guzzlord GX: http://www.pokebeach.com/2017/08/buzzwole-gx-and-guzzlord-gx-revealed-at-worlds
Pros:
Basic Pokemon with 210 HP.
Dark Type with no good Fighting decks in the meta.
Tyrannical Hole hits for 180 base, 210 Banded, 230 Banded+Kukui
Glutton GX allows you to take two extra prizes.
Resistance to Psychic>Grabodor GUR.
Searchable with Heavy Ball
Cons:
Eat Sloppily is useless. You mill your deck for energy acceleration, which means you have to play more energy and less consistency cards. Not to mention you mill said consistency cards.
Tyrannical Hole and Gutton GX have a FIVE energy cost. That is too high, and regardless of the damage/utility out of the attacks, makes this card unplayable.
Retreat cost of 4 means you still have to discard 2 with Alter of the Moone up. You could play four Guzma, but then you're playing Guzma defensively not offensively. Float Stone blocks the Choice Band Damage. Zoroark Step-In makes the deck less consistent with an added Pokemon like that doesn't contribute to your win condition.
Glutton GX has 100 base damage. Meaning you either use it on a 1-prize basic/stage 1 (i.e Beldum or Kirlia) to take 3 Prizes, or you have to damage something with Tyrannical Hole (Which is going to OHKO most things when Banded) and hope they don't have a way to heal that Pokemon (most likely will be Metagross or Gardevoir).
Overall, this card is terrible. If the attacks were one Dark energy less each, and Eat Sloppily didn't mill but instead shuffled the other cards back into your deck, then this card would see play.
Nihilego GX: http://www.pokebeach.com/2017/08/buzzwole-gx-and-guzzlord-gx-revealed-at-worlds
Pros:
Synergy with Alter of the Moone.
Cons: (Spoiler-Basically everything)
180 HP means it's easily OHKO'd by everything Tier 2 and above.
Psychic Typing isn't good and even worse it has a Psychic Weakness.
Nihilistic Light affects YOUR Pokemon as well. If it didn't then MAYBE you could play it in Alolan Muk GX.
Lock UP cost three Psychic and only does 120. The effect is easily worked around by Guzma.
Symbiont GX cost three Psychic to give your opponent 2 more prizes, which they will in turn immediately take off of this squishy GX.
By far the WORST of the UltraBeasts we've been shown so far. Literally everything about this card is bad.
Kartana GX: http://www.pokebeach.com/2017/08/kartana-gx-and-regice-from-sm4-revealed
Pros:
Cut Down has energy disruption that affects a fair amount of decks in the Tier 1&2 bracket.
Blade GX can steal games since it only cost 1 Metal Energy.
Retreat Cost of 1.
Cons:
Meta Typing means weakness to fire. (Metal Typing would normally be good because of Gardevoir GX and Alolan Ninetails GX, and the resistance to Garbodor GUR, but because of Kartana's HP and Gale Sword's damage this is a bad thing.)
170 HP.
Gale Sword while only costing a Metal and a DCE has a 70 base damage. 70. Base. Damage. that's 100 with a Band and 120 with Band+Kukui. While the 120 is good in the Gardevoir and Ninetails match-ups, it's also a conditional number to hit that gets harder with the loss of VS Seeker. And with its small 170 HP, can easily be return OHKO's by both of those Pokemon.
You could play this as a 1-of in Metagross, but there's way better 1-of techs to play. (i.e Genesect EX, Necrozma GX, Cobalion STS)
In total, all four of these Pokemon are bad. None of them are game changing and only Buzzwole GX might actually see competitive play. Unless there is heavy support for these guys (something like the Plasma Support that Deoxys EX, Luiga EX and Thunderus EX got) none of these four are playable. And SM4 as a whole is looking REALLY bad.
Buzzwole GX: http://www.pokebeach.com/2017/08/buzzwole-gx-and-guzzlord-gx-revealed-at-worlds
Pros:
190 HP which is crucial for the big basics in the current meta with things like Gardevoir and Metagross around.
Jet Punch hits active and one bench for 30 each for one energy cost.
Knuckle Impact hits for 160 which can be buffed to 190 (All big basics) with a Choice Band and 210 (All Stage 1 GX's) with a Kukui+Band. Attack can be reset by Guzma/other switch methods.
Has synergy with Carbink BREAK, Registeel EX, Brooklet Hill and Scorched Earth.
Absorption GX has a massive 240 Damage cap un-buffed.
Cons:
Fighting Type. With only Darkrai as the primary fighting weakness, the Fighting typing doesn't favor Buzzwole moving forward. There isn't and Electric Type Pokemon that are announced that will hit the top of the Tier List (Raichu GX is a worse version of Darkrai EX, and we see how Darkrai EX is dropping on the Tier List), nor is there a Dark Type Pokemon that will show on the Tier List (we will talk about Guzzlord next). You could argue that it has good typing against Drampa GX and Silvally GX, but that's not enough to warrant the a Fighting Type to be good.
Weakness to Psychic<Garbodor GUR.
Retreat cost of 2. The reason why cards like Gardevoir GX can have a retreat of 2 and not be hurt by it, is because it plays DCE. Buzzwole GX however, doesn't want to play DCE, so that cost of two is now expensive. Not to mention it limits the searching ability to just Brooklet Hill and Ultra Ball.
Absorption GX is an expensive, early game attack only. With the attack lowering in power with every attack, 240/200/160/120/80/40, you can see that its GX attack is only useful within the first three prizes when dealing with decks like Fire or any Stage 1 GX deck and even then it's only useful in the first two prizes when dealing with Metagross and Gardevoir. With a cost of THREE Fighting energy, it's also extremely expensive early on.
Knuckle Impact is also too expensive. Having a cost of three Fighting energy hinders this card greatly. Has it been a Fighting and a DCE, that open the door up for this card to have an impact on the meta. But where is sits right now, you HAVE to pair it with Carbink BREAK for the energy acceleration. It also helps Gardevoir be closer to the OHKO range. Three energy on Garde+Choice band is a OHKO, or just 4 energy on Garde is an OHKO.
This is the most playable out of the UltraBeasts and it has too much going against it to be past Tier 3.
Guzzlord GX: http://www.pokebeach.com/2017/08/buzzwole-gx-and-guzzlord-gx-revealed-at-worlds
Pros:
Basic Pokemon with 210 HP.
Dark Type with no good Fighting decks in the meta.
Tyrannical Hole hits for 180 base, 210 Banded, 230 Banded+Kukui
Glutton GX allows you to take two extra prizes.
Resistance to Psychic>Grabodor GUR.
Searchable with Heavy Ball
Cons:
Eat Sloppily is useless. You mill your deck for energy acceleration, which means you have to play more energy and less consistency cards. Not to mention you mill said consistency cards.
Tyrannical Hole and Gutton GX have a FIVE energy cost. That is too high, and regardless of the damage/utility out of the attacks, makes this card unplayable.
Retreat cost of 4 means you still have to discard 2 with Alter of the Moone up. You could play four Guzma, but then you're playing Guzma defensively not offensively. Float Stone blocks the Choice Band Damage. Zoroark Step-In makes the deck less consistent with an added Pokemon like that doesn't contribute to your win condition.
Glutton GX has 100 base damage. Meaning you either use it on a 1-prize basic/stage 1 (i.e Beldum or Kirlia) to take 3 Prizes, or you have to damage something with Tyrannical Hole (Which is going to OHKO most things when Banded) and hope they don't have a way to heal that Pokemon (most likely will be Metagross or Gardevoir).
Overall, this card is terrible. If the attacks were one Dark energy less each, and Eat Sloppily didn't mill but instead shuffled the other cards back into your deck, then this card would see play.
Nihilego GX: http://www.pokebeach.com/2017/08/buzzwole-gx-and-guzzlord-gx-revealed-at-worlds
Pros:
Synergy with Alter of the Moone.
Cons: (Spoiler-Basically everything)
180 HP means it's easily OHKO'd by everything Tier 2 and above.
Psychic Typing isn't good and even worse it has a Psychic Weakness.
Nihilistic Light affects YOUR Pokemon as well. If it didn't then MAYBE you could play it in Alolan Muk GX.
Lock UP cost three Psychic and only does 120. The effect is easily worked around by Guzma.
Symbiont GX cost three Psychic to give your opponent 2 more prizes, which they will in turn immediately take off of this squishy GX.
By far the WORST of the UltraBeasts we've been shown so far. Literally everything about this card is bad.
Kartana GX: http://www.pokebeach.com/2017/08/kartana-gx-and-regice-from-sm4-revealed
Pros:
Cut Down has energy disruption that affects a fair amount of decks in the Tier 1&2 bracket.
Blade GX can steal games since it only cost 1 Metal Energy.
Retreat Cost of 1.
Cons:
Meta Typing means weakness to fire. (Metal Typing would normally be good because of Gardevoir GX and Alolan Ninetails GX, and the resistance to Garbodor GUR, but because of Kartana's HP and Gale Sword's damage this is a bad thing.)
170 HP.
Gale Sword while only costing a Metal and a DCE has a 70 base damage. 70. Base. Damage. that's 100 with a Band and 120 with Band+Kukui. While the 120 is good in the Gardevoir and Ninetails match-ups, it's also a conditional number to hit that gets harder with the loss of VS Seeker. And with its small 170 HP, can easily be return OHKO's by both of those Pokemon.
You could play this as a 1-of in Metagross, but there's way better 1-of techs to play. (i.e Genesect EX, Necrozma GX, Cobalion STS)
In total, all four of these Pokemon are bad. None of them are game changing and only Buzzwole GX might actually see competitive play. Unless there is heavy support for these guys (something like the Plasma Support that Deoxys EX, Luiga EX and Thunderus EX got) none of these four are playable. And SM4 as a whole is looking REALLY bad.