I couldn't find any other threads dedicated to this game in the subforum, so I thought I should start one on what many people said would be the new pokemon.
I'm going to start off by saying that I think that these games are actually two completely separate entities that I don't believe should be considered direct competitors. They share some similarities in terms of the fact that you have a team of 6 monsters/ spirits that you use to battle, but other than that the two games are very different experiences for me.
The battle system itself is extremely different to pokemon, and I find it quite enjoyable. Early on in the game, I relied heavily on soultimate moves but I almost never used any attacking soultimates anymore. The auto battle system might be a little random at first, but with the right training and teams it can be really strategic.
The story itself was childish in its themes generally (with a couple of weird bits that were much more adult) but I felt like it did a really good job of appealing to issues faced by the people of its target audience. It had a real charm to it and I found myself getting really engaged in the story, despite its simplicity. The characters were vibrant and varied despite some of their limited screen time and I found the dialogue quite charming. The human character designs were generally pretty cool too!
As for the yokai themselves, while there were some I didn't care for that much, I found myself really liking a lot of them. I also found that I didn't grow too attached to the early yokai and I was prepared to let them go for better ones for later parts of the story. I do like the watch rank mechanic that allowed you to find new and more powerful yokai in areas that you had been before which allowed the area of the game to not get too huge!
The post game is also really enjoyable with heaps to do. You have to train up a new team of S rank yokai, but I've grown a fair bit more attached to some of them than my main team! I've nearly finished the main post game earlier (I've only got the hidden boss left to go) but there is still a lot to do in the post game.
The game definitely isn't perfect though. I find the recruitment mechanic to be rather obnoxious at some points, especially with higher rank yokai that it can take you half an hour to encounter. Apparently this is fixed in the second game although I don't know how.
It is also quite hard to find a place to get good exp in the later game without resorting to using holy exp orbs from manipulating daily challenges and when a lot of the good S ranks come from the crank a kai at level 1, this is a bit irritating.
The crank a kai itself is a pain to deal with. It is the way to get a lot of good stuff in the game (and a lot of the best yokai) and its 3 uses a day mechanic makes it difficult to get what you want.
Overall, I'd be interested to hear what other people thought of the game!