Engadget:

Hasbro's Super Mario Bros.-themed Monopoly looks delightful enough as it is, but it might feel a bit lacking if you prefer the kart-driving version of the beloved Italian plumber. The good news is that you won't have to make do with the ordinary Mario Monopoly -- not when toy and board game giant has released Monopoly Gamer: Mario Kart. Like its predecessor, it incorporates Kart characters and twists into the game.

There have to be people who just collect these Monopoly variants, right?

Otherwise, I figure you just buy the one version you like and call it a day.