In my opinion, Dusk Mane Necrozma is better than Dawn Wings Necrozma because when Necrozma learns Sunsteel Strike, it can guranteed 2HKO Uber Geomancy Xerneas. It is immune to Poison type attack like if anyone tried to use Toxic or any Poison Type moves on it. Its ability Prism Amor make it better as well because it takes 3/4 from super effective attacks. It resists to Psychic, Dragon, Fairy, Flying, Grass, Ice, Normal, Rock and Steel Type Users. But it is weak to Dark, Fire Ghost and Ground Type Users. It can KO anything with its Signature move Photon Geyser and having it learn Swords Dance make it stupid strong and broken as well. Photon Geyser becomes a physical attack if the user's Attack is greater than its Special Attack, including stat stage changes. This move and its effects ignore the Abilities of other Pokemon. Earthquake is just for a STAB purpose if it meets any Steel Type user or Dusk Mane Necrozma. It should be holding the Ultranecrozium-Z for it to undergo Ultra Burst to transform into Ultra Necrozma. It is stupid fast when it is in that form too. But it will be weak to Bug, Dark, Dragon, Fairy, Ghost and Ice Type Users. It resists Electric, Fighting, Fire, Grass, Psychic and Water Type Users. Its ability Neuroforce make it more OP and broken because Ultra Necrozma's attacks that are super effective against the target will do 1.25x damage. Its strongest Z-Move Light That Burns The Sky can gurantee to KO anything that stand in its way. It is a very powerful Z-Move. Light That Burns The Sky becomes a physical attack if the user's Attack is greater than its Special Attack, including stat stage changes. This move and its effects ignore the Abilities of other Pokemon. This is why Dusk Mane Necrozma is better in my opinion.