I loved the Monopoly Gamer version, and gave it 4 out of 5 stars in my review. However, the one problem I had with the game (and why I didn't give it a full 5 stars) was because of the parity between each character's abilities. The "expansion pack" figurines only make this worse.
In the original game, it is far easier to win this game while playing as Donkey Kong than it is with Yoshi just due to the nature of their "power-ups." Though I am appreciative the novelty of each character having specific nuances, I would've liked a little more of a fair playing field. However, the expansion pack characters are so powerful that it renders some of the original characters essentially as a handicap.
This game is still fun, and I still recommend getting the extra figurines because it does add a unique component to the game, but I'd recommend maybe choosing your character randomly, otherwise I imagine most gamers will fight over who gets Boo and Fire Mario and Toad.