Imagine thinking Mega Metagross is actually better than Solgaleo in any way

>Defensive calcs
>252 Atk Garchomp Earthquake vs. 0 HP / 0 Def Solgaleo: 308-366 (74.2 - 88.1%) -- guaranteed 2HKO
>252 Atk Garchomp Earthquake vs. 0 HP / 0 Def Metagross-Mega: 230-272 (76.4 - 90.3%) -- guaranteed 2HKO

>252 SpA Gengar Shadow Ball vs. 0 HP / 0 SpD Solgaleo: 288-342 (69.3 - 82.4%) -- guaranteed 2HKO
>252 SpA Gengar Shadow Ball vs. 0 HP / 0 SpD Metagross-Mega: 242-288 (80.3 - 95.6%) -- guaranteed 2HKO

>Offensive calcs
>252 Atk Life Orb Solgaleo Flare Blitz vs. 248 HP / 28 Def Celesteela: 335-395 (84.3 - 99.4%) -- guaranteed 2HKO after Leftovers recovery
>252 Atk Tough Claws Metagross-Mega Thunder Punch vs. 248 HP / 28 Def Celesteela in Electric Terrain: 330-390 (83.1 - 98.2%) -- guaranteed 2HKO after Leftovers recovery
>Can't outdamage even with Electric Terrain Support

>252 Atk Life Orb Solgaleo Sunsteel Strike vs. 0 HP / 0 Def Mew: 220-261 (64.5 - 76.5%) -- guaranteed 2HKO
>252 Atk Tough Claws Metagross-Mega Meteor Mash vs. 0 HP / 0 Def Mew: 207-244 (60.7 - 71.5%) -- guaranteed 2HKO

Solgaleo has a better offensive movepool, does more damage along LO, has better bulk and has access to Morning Sun to regain health, BASED