Mario Kart 7 is the Newest installment in the Series and while its the best its not without Flaws.
Gameplay: is just as good and the best in the series there are more Gameplay elements like going Underwater, Gliding, and just the normal racing the Track Design is some of the best of the Series with some tracks from previous MK games like the Wii Tracks and some of the DS Tracks with some Nes Tracks and some new ones there are 16 Characters to Choose from including your Mii, there are different Vehicle Combinations to pick from like there are a certain amount of Wheels, Gliders, and Karts to choose from to mix up overall the Racing is just as good as the previous MK games before it.
Graphics: there good not as good as Super Mario 3D Land but there still good.
Replay: there is loads of Replay Value like Multiplayer, Grand Prix, Time Trials, Balloon Battle and Ghost mode.
Best Racing in the Series/Best Track Design/Good Underwater and Gliding Elements/Good Graphics/Good Replay Value.
while items have been Rebalanced its not perfect/some Modes from the DS MK have been Removed.
Overall: its the best in the series, while items are better there not perfect so while its the best its not perfect.