I love this game. It's definitely one of my favorite Mario Partys of the group. I don't know exactly how I'd rank them, but MP7 is safely in my top 3 no matter how you slice it.

The maps are pretty good - Pagoda Peak was always my favorite! And the music to Pagoda is spectacular as well. There is some variance from the traditional run around and collect stars mechanic I like most, but they don't go off the rails in this one and it at least keeps some influence from the traditional MP games.
The thing this Mario Party game does the best is the minigames! Track & Yield, Fun Run, Target Tag, Light Speed, Camp Ukiki, Bob-ombic Plague, Shock Absorbers - just to name a few. Heck, even the Bowser Minigames are enjoyable in this one.
This brings me to my next point - 8 players. Mario Party has thrown at us some weird things over the years that really takes a step away from traditional MP gameplay, but the idea of adding more players has to be one of the best ones I've seen so far. Granted, I think it would have been a bit more fun with each having their own controller, but with the 4 player restriction on the Gamecube I'm not complaining about this addition. Of course, they just let you play the classic way as well if you'd like, which is awesome. *cough* Mario Party 10 *cough*
I've certainly had some great times with this game. It does have some stiff competition, particularly with the other GC era Mario Party games, but this is one of my favorites to date. I still remember bringing this in our TV-equipped minivan to play on our family road trips ten years ago - times I'll never forget!
Hopefully when I return home next week from college I'll be able to play it some more.