Are you looking for a new Idol Rhythm game to satisfy your needs? Then go ahead and Pre-Register for Tokyo 7th Sisters. Love Live! School Idol Project is a similar title and it was very popular when it first came out, so this new idol game might just be the next big thing!
Apparently the gameplay is supposed to be a mixture of Million Arthur, Love Live, Project Diva, and Cross X Beats! That sounds really confusing, but you can find a gameplay of video of the rhythm part here.