- Great 115 Defense and 130 special defense, combined with decent 95 special attack
-Tapu Fini's Water / Fairy typing allows it to be one of the best Mega Charizard X answers, as well as letting it take on other common Fire- and Dragon-types like Air Balloon Heatran and bulky Zygarde.
- It's bulk lets it take attacks from Landorus-T and Golem, while the ability Misty Terrain allows it to take on common sleep users like Vivillon and Jumpluff.
- Tapunium Z along with Taunt also helps it shut down common stall Pokemon like Chansey and Necrozma.
- Struggles with Pokemon like Mega Metagross, Ferrothorn, Mega Venusaur, Magnezone, Togekiss, and Zeraora because of their bulk or their super effective attacks.
- A Waterium Z set also has trouble with dealing with special walls like Chansey, Meloetta, and Mega Slowbro
So, I'd say Tapu Fini is a good Pokemon to use in 1v1.