Personally I like Adeku more because I see him as more of a "real" person. I like Shirona as a whole but I feel as if she's portrayed too much as the all-knowing woman who is insanely powerful. I think that sort of character works in the games where tbqh, its much harder to give a character several attributes but in the Anime I feel that this can be done.
I've also never fully understood the appeal in the messages that Shirona tries to convey. The "something will be born" message doesn't say anything as I see it. In the Anime Pokéverse you almost seemingly become friends, rivals or enemies (where rivals can be slotted into either friends or enemies depending on who it is). While they make Satoshi and co ponder what she means its not something that really effects them; they just ponder for the sake of it. However with Adeku when he talks about what the gang want to do once they've acheieved their goals it actually seems like something to consider and something the audience would wonder as well. I doubt we'll ever see any character ultimately achieve their goal and I think that's what make the thinking part of his message even better - its something you can actually speculate about.