I started as F2P player, but made some bad decision during event that forced me to buy some diamonds. As for now my total spending is 6960 JPY.
Laddering totally depends on your chosen member. Some are crazy AF. Some are totally lax. I got 1st in Utagawa without spending any money. Even before I ever spent any money, I could get Top 3 on each Kanazawa Yuuki (SUPER GiRLS) 2 times and Fujii Yui (URA-KiSS) once.
Graphics: Bad cuttings, but some idols look uberly cute in various poses.
Sound: Love the dialogue cues.
Gameplay: Pretty standard. But big improvement compared to Girls Beat Stage.
Story: Template, but some parts are modified for each member, sometimes including local dialect.
Value: You can play it for free and still be competitive - at least if you start early...
P.S.: Free to play players be warn focus in the idol you like the most because it gets harder to get story unlock coins soon after.
and for some reason I can't play the event song all the time
if anybody know, please tell me