I got a choice of free games/accessories offered to me by Microsoft when my 360 broke twice within two weeks and chose this as my free game.
I remember being initially suprised when way back at E3 2007 during the MS presentation this was one of the titles that received its fair share of air time because on the face of things cute graphics aside it looked like a title which brings nothing new to the table and is far from a revolutionary console selling title. Majority of people have played either Mario Party in some form or Fusion Frenzy and this is the format that VP:PA follows.
What really clinched my decision to get the game though was the demo that was released over Xbox Live. It had lots of character, nice visuals, wacky mini games which I knew were going to be even more fun over Live and generally the game was a good break from more in-depth titles and sure enough the full game doesn't dissappoint
What I would add though in closing is that if in any doubt or perhaps if you consider yourself a "serious"/"older" gamer then a quick blast of the demo over Xbox Live may be in order as I saw alot of gaming sites really slated this game as repetitive/kiddy/uninspired etc - its clearly a love /hate game.