Gacha is stingy and brutal, events are ridiculously grindy and game takes a significant time per run, not bad or good, just keep it in mind. Hopefully after they cash a few more billion yens they'll make gacha slightly less ruthless.
The raising of the girls is great, they ticked so many good points in the raising sim part, only being hampered by your need to gacha (and it's not cheap) to enjoy it.
My gripe, and the gripe of the entire community, is how incredibly bad the races are. The race system is BAD, like -10/10 bad levels. They are buggy, your horses IA is trash, results are random, advice given is useless, some skills are useless, and the list goes on... Having excellent training and being overly qualified for a race you can randomly lose for no real reason, this isn't so bad except you need to wait another goddamn 30 minutes to reach the race again and lose to RNG again (or win, just get lucky).
I strongly recommend to install the game, raise a few girls to enjoy the ambience and whatnot... then uninstall a week later. It really is great to play around for a while, but it gets ridiculously stale, grindy and frustrating after a short while.