Buy it, use it, make it, fix it, share it, race it, rate, remix it.
MNR is addictive, in every sense of the word. Firstly, the racing mechanics are solid. They are perfectly polished, and they provide you with precise control and a wide array of tactics. If this game didn't contain the creation power discussed below, it would still be worth your money. The single player career races can be more than a little frustrating, sometimes the AI will gang up on you while ignoring one specific AI character, making 1st place a real fight. There are 3 versions of every weapon, shields, boosts, superjumps and much more to aid or hinder your breakneck race to the finish line. Add to that achievements, tokens and challenges in each race, and the single player campaign measures up nicely. But you won't have to spend too much time racing against the AI, because the real goodness is in the online racing. Less lag than anything else I've played on my PS3, and some very good match making too. Its incredibly hard to stop playing match after match because of the excitement and suprise waiting in the next one.
Do you want to race as Bugs Bunny driving an ice-cream truck? Homer Simpson in a pink station wagon? Mr Peanut in the car from Deathproof? MNR has you covered. Not only can you create anything you can think of, but you can share and download with everyone else playing MNR online. This makes for an endless supply of characters and karts. But those are nothing without tracks, and MNR has the most tracks of any racer, ever.
You can create VERY sophisticated tracks in MNR. Spend 30 mins whipping up something fun and fresh, or spend 8 hours tweeking your masterpiece. A wide array of simple but powerful creation tools can make even the most hopeless creator halfway decent. I've never had a knack for creating, but in MNR, I feel like a game designer.
Mario Kart has reigned as the king of kart-town for over a decade. But that rule has ended. MNR does the impossible by surpassing the gold standard for fun, chaos filled racing. The only reason to avoid this game is if you don't like to have fun.