I'm well-informed of the game (one of the main members of Nintendo Wii Fanboy... see if you could tell which one I am, haha)... and I just got the game today... but just barely...
Yeah... we were kinda' low on money... we recently spent a huge load on anniversary, so I had like few dollars on my credits and cashes... So...
But we got it! Barely, but still got it!
I'll try it out tonight.
But as far as "how I generally think of it" :
It's
Mario Kart. What can go wrong?
Even Double Dash was amazing if you played copious amounts of it!The online system works wonders, even with going against people
WORLDWIDE.
I heard people had complaints of the
ranking system though... lots of people rocket through the sky, then fall flat on their faces in rank in less than 3 matches.
As for karts and bikes.
Bikes may seem great, but they can't go to orange sparks in added boosts, and wheelies and tricks (of which they use to speed themselves up) can easily be interrupted by being bumped from the side.
Lots of people hated how advantageous bikes were to karts (seeing how they could beat any kart's top ghost time)... but the above flaws can easily ruin them in a full-kart race.
I just hope the battle-mode will be extra fun.
I've seen tons of videos, but it's nothing compared to actually PLAYING it.

I'll give a full review when I try it tonight (currently in library)...