>>43837838SOS chaining makes shiny hunting a lot easier and it has one of the better breeding spots for efficient egg hatching so if shiny hunting is what you want than USUM is good for it. It's also the only version in the foreseeable future where you can get shiny ultra Beasts. As a game in general it's fun and enjoyable if you can get past all the cutscenes. I beat it last night actually.
