The new iPad's camera is far better when comparing it to the iPad 2s camera. That being said I would not find it good enough to be my primary camera (setting the impractical size aside). It is a far improvment from the ipad 2 but it is in no way as good as say the iPhone 4s which I use as my primary camera now.
It's a point and shoot camera. None of those are GOOD. It's a relative thing. As an extra part in a tablet, it is competitive with other simple p&s cameras.
Common problem is the lens gets dirty, this will affect the image quality, aside from that it is a decent mobile camera, I use mine mainly for scanning documents.