I made two Miis for it, Xiahou Ba and Hi-Fi Trip. I've played only the demo. I won't pretend I didn't have fun with making them both and plopping them on the island (and giving Hi-Fi Trip an extremely low pitched voice), and it would be fun to sit down and make some more Miis, but honestly, a lot of this game feels like it has to be shared to others online with deliberately taken out of context madlibs in order to have fun with it, and I foresee that'll hurt this game's longevity for long-term play, especially once scenes and dialogue bits start to repeat. As I said, it is fun to see what happens because things can get unpredictable (it's one of the reasons The Sims is extremely popular), but you can really only experience this in the first few hours before scenes play out exactly the same and the game wears itself out. I already foresee this from this initial dialogue bump I had with both Xiahou Ba and Hi-Fi Trip.
A huge chunk of this game is making things yourself, and the fact that Nintendo disabling sharing Miis, pets, food to others, etc hurts it massively, as opposed to other games in its genre (like The Sims). I'm an adult with a day job and irl responsibilities, I no longer have the free time I used to to be able to meticulously draw items for my island, and being unable to find something I like online and just plop it in isn't worth the ludicrous time investment the game requires to have fun with Miis. This isn't a skill issue, it's a time one, and you need a lot of time to make something that looks good.
Anyway, will I get the full game? Probably not. It's not a game that'll stick with me in the long term the way The Sims, Spore, and Garry's Mod did. If I wanted a life Sim game where I can plop my OCs and Dynasty Warriors characters in the same house and watch them do things, The Sims 4 already got me covered. If I wanted to make basically any character I like and design a world where said characters can interact as creatures, I'd go play Spore. Garry's Mod fits my scenario making where I can snap pictures of characters doing things.