The gacha rate for highest rarity (3*) is 3%, not that bad considering there's other game that have worst rate. Also we get a lots of gems easily from game and a big amount of gems from their daily log in for a week, as part of their launch celebration.
The game is quite chill and not very demanding for you to invest a lot of time playing it. It have PvP too and honestly it's not bad, fun enough to compete with your skill with puzzle games.
While the graphic and character design might not for all people taste, it's still a good, solid, and fun games to play. Really recommend it for anyone who interested with this game, to at least try playing it a bit.