From what I've played, it's way better than I expected it to be so far. Hope it stays that way for the rest of the game, I don't want to be let down by it. The original is in my top 5 GC games.
I just purchased Luigi's Mansion: Dark Moon, too. I'm a huge admirer of the original title, and I sincerely hope that this sequel greatly expands upon its predecessor's core concepts.
Project Diva, whatever one just came out for the PS3. (lol I don't even know what it's called.) It's a Vocaloid game, and it's really great. I'm enjoying it so far. =D