One of the most frequent questions at this moment is who should we power up, Mewtwo or Raikou? Which one is better to use and why?
You need to power up Raikou first. This is just because he will stop being available by the end of this current month. Because of the ambiguity for the future EX raids, nobody knows when the Mewtwo raids will stop.
The Legendary Beast, Raikou, has more favorable matchups in the gyms than Mewtwo, and it can help with Blastoise, Lapras, Ho-Oh, Suicune, Articuno, Moltres, Charizard and Lugia raids, and Vaporeon solos.
We can say that Mewtwo is probably the best Psychic attacker. Mewtwo is also the best neutral attacker, and also excellent Ghost attacker. It can be used for the raids against Muk and Weezing, Machamp, Gengar, and Alakazam solos. It can be also used as a great attacker against itself. Because Ground moves are not the best, Mewtwo is easily the smartest choice to use against Raikou.
Final words – They’re both useful and both can be powered up. A lesson learned is that you should power up your Legendary right after the moment they stop being available. Nobody wants to throw Stardust and Rare Candy into powering up a 76% IV Mewtwo, only to catch an 85% the following days.