I too bring gifts:
Also my impressions of the game after playing through the tutorial section:
OFA definitely feels like idolmaster 2.5. Everything feels so familiar yet there are small changes that makes it almost fun to play even if you have already played number 2 (though I haven't or wasn't shown that you had to stick to a strict schedule to hit #1 in some music ranking yet). Best of all - no more Janken after work, thank god!
One of the better things I like about this game is that the idols now have a sort of grid on how you want to "level up" your idols. Yayoi being week in dancing? Let's level her up on that area. As you progress with your idols you unlock more of the grid, and it opens up what I assume are story events.
Lastly, the auditions and FES segments, I don't know if it's me, but the timing seems more forgiving. Futari no Kioku was the first song I use and twice I full combo it without even trying. I had a go at CHANGE and READY and I seem to be getting a lot of perfects, with hardly any greats or goods.
So really, while the game is essentially the same at it's core, the improvements done over it makes me pleased with my purchase.