MP2 is a much better game. Although some gameplay improvements were made, such as the ability to have three items at a time, the levels and feel of the game are lacking, and it seems rushed in this way. I want goofy little witch hats and pirate outfits, levels that have a feel to them, and I want king bowser to walk around the board taking peoples' coins. MP3 took all of these fun things away, and that, IMO, was a mistake that all the Waluigis and Waluigi's Islands in the world can't make up for... or something.
If you're looking for a party game, get Mario Party 2, and leave this one to collect dust on the shelf.