Bought it solely to be played with my wife. Works like a charm.
It's your typical kart-game with a twist in a form of transforming a kart into a bouat or a plane. There are powerups both offensive and defensive, boosts and what not. The transforming bit makes the game fun, since you need to master all three forms to get the edge on hard settings. AI is pretty balanced, it's easy on easy, on per with medium and a bit cheating on hard - business as usual. Tracks are numerous (20 + few bonus tracks + mirrors of all) and themed after different SEGA games, with most of them shifting courses on different laps forcing the transformations.
Game modes consist of World Tour, Grand Prix, Single Race and Time Attack. World tour is the campaign mode, where you can unlock new characters by collecting stars for winning various events. GP is a 4race tournament for points (the higher the finishing place, the more points you get), Time Attack and Single Race is sefl-explainatory.
On the visual side the game looks nice, it's as colorful as a kart game could be, but in a good way, sound effects are also nice along with character taunts when overtaking. Music is nice, fits the tracks and races quite nice.
The game supports up to 4 player split-screen along with normal online multiplayer.
All in all a fun game to play sometime with famili and/or friends who "don't dig that gameing thing". Single GP tournament is about 15-25min, what makes it quite easy to fit in a party event.