Guitar Hero Arcade is based on GH3 and will be terrible. From what I've seen, it's going to 1 credit = 1 song and I really hate GH3's timing in general. The fact that Konami's making the cabinets is pretty funny though. At least the guitars should be near-indestructible.
Empress is so far amazing. Music-wise, it's better to me than Troopers was by quite a bit.
I have to say though, I've been turned off from the series since 10th Style. From 6th-10th, the music and everything was so amazing and after that, a lot of artists started leaving and getting replaced and I'm not sure what's happened but I'm just not as excited by the game as I used to be.