The graphics were Gamecube level at best and really the only new addition that it seemed to bring to the series was extensive use of the motion controls. The mini-games all appeared to variations of older Mario Party games or of a very similar theme, though at the rate Mario Party games are released I guess thats not a huge surprise. Luckily, the magic of the Wiimote did allow them to mix things up a bit by including games like shaking up cans of soda until they burst or lassoing barrels off a platform. It was a fun enough title to play, and made good use of the controller, but it still managed to feel stale. Maybe it was the lack of friends around to play it with, or maybe after this long the series just needs a bit of a break. And of course, there is no online play.
If you are a huge fan of the previous Mario Party titles, then I'd say its worth giving this one a shot when it comes out next week. Otherwise I'd heavily recommend giving this one a rent to see if the motion-sensitive gameplay is really worth partying with Mario again.