It will be easier to decide that when it goes on sale and there will be customer reviews. It will be launched on 18 November so you won't have to wait too long.
There are two versions, the basic at $300 and the Deluxe at $350 - this has a bigger hard drive and some extra games and other features. As for whether it's worth buying, generally nobody is pretending that it's revolutionary. There will later be new features like more multiplayer games, but you may have to buy other equipment to use them all. People are also unclear whether this will be much more powerful than the current Wii - if not, many have said they won't bother.
On the other hand, the keenest users of the new Wii U are likely to be children - and parents of young children are already planning to buy them for Christmas, so you can expect sales to be high.