Alright, having played the game some now I feel I can weigh in on it (I have a few #1 records, and a few other really high score with gold stars).
Game is fun. Definitely not at the level of Amp/Freq, but that's because the focus has definitely shifted to high scores, not progression and completion.
There are some serious long-term problems though. For some reason it's a high score game that discourages retries for high scores. This gets a big WTF from me. Instead you're encouraged to drift from song to song, either for bonus coins or facebook goals. If you keep trying for high scores on one song you're just going to bleed coins.
Easy fix: 5 starring a song should give you enough coins to break even. Harmonix, let me play your game without grinding songs I'm not interested in.
The other, less serious problem, is the how useless the other power-ups are. If you aren't rolling with Jackpot, Flame, and the right instrument boost, you might as well not play. Jackpot at least keeps things fun and tense, and is the closest thing in the game to that oldschool Frequency rush.
Edit: An alternative fix - don't make restarts eat your coins