The odds are if you're old enough to read this review then Wii Party U is probably not for you. My young kids love it (ages 7 and under), and really seem to have a blast. But for me this board game/mini-game collection gets tedious really fast.
Basically it's a board game, where occasionally you and all the other players compete in mini-games for prizes or advantages. The games are all either based entirely on luck or the most basic control schemes. Nothing here ever felt like a game of skill.
And just to be clear, I do enjoy "board game" games and mini-game collections. I thought the Mario Party games, Fortune Street, Wii Sports, and We Ski & Snowboard were all a lot of fun. This on the other hand is just too simple to be fun, and seems to be targeting a very young or very unskilled audience.