I got it too!
Some tidbits of info (*minor spoilers*)
-The game makes you think there are 16 characters to play with, but actually there are 24 (example: Baby Peach)!
-Wii Wheel works fine, just a little learning-curve of aprox ~15 minutes. Then you can race rather well! I still do time-trials with me old cube-controller though 
... But that's just because i played 100+ hours of Double Dash.
-Wii Wheel retails for 12.50 euro's.
-Mario Kart Wii (including 1 Wii Wheel) is 49.95 euro's. So you actually pay like 37.45 for Mario Kart Wii, which i think is very nice of Nintendo.
-32 Tracks, some are really cool, Character-models are slightly uglier then the Gamecube-ones. Though still looking 'good enough'.
-The game makes you think there is only 50, 100 and 150Cc but ofcourse there still is a mirror-mode.
-Online works well, could get into a game easily!
-Online works this way, you start with 5000 points. Everytime you lose you lose some points (for example 12 points or something) and if you win you gain some... So you still have a little 'competitive stuff' in the online... Although there are no leaderbords.
-You can download 'ghosts' of people who had slightly better times on courses then yours, this is to try and push you to get a better time.
- 'Drifting' works a little more anoying in this version, although i guess it's just getting used to!
- Coolest map is one where you drive through a mall! Although alot of the new ones are totally awesome!... Props for the leveldesigners @ Nintendo!... Because there are a lot of small shortcuts and other routes you can take in almost every 'new' map... And eehrm, 'older' maps have gotten a graphical update (especially Delfino plaza, compared to the DS one)
And owyeah, i got it 3 days before launch! Those people @ the gameshop i go to know me quite well (go there like 2-3 times a week and they said they had it in... I could get a copy from them 
)... Sweet people over there!
EDIT: 5 friends of mine have already bought it too, i'm going to have a massive multiplayer with them on Saturday! Should be sweet!... I'll make a thread about the mario kart Wii multiplayer in a few days!
THE NETHERLANDS
