Hm, I really liked the episode, I thought it was pretty good. Oh wow, the Master Class looks amazing, I really like where it's taking place, inside a castle! It really fits with Pokemon Showcases and it's theme of "Kalos Queen" which is what I like about it.
So it looks like all of Serena's rivals have met. Serena's reaction was funny when Miette asked Ash if he would cheer for her and over Serena and he says if it's Serena, he'd choose her, then she asks if they are a couple lol. She looked worried asking him. All the girls know about Serena and Miette love rivalry for Ash.
I also liked how Serena had to use her 3 Princess Keys to open the door, it looked nice. It's cool that Korrina, Alexa, Goodra, etc. Are also watching Serena's Master Class. I don't know why Grace wasn't sitting next to Ash and the group. Anyway I liked the performances, Serena's performance was great along with the music. It was sad when her rivals lost and were crying telling her to win. I'm looking forward to the next episode! 8.5/10.