The first thing that surprised me is its 12.1-megapixels. The barrier of 10 megapixels is no barrier anymore for private user. Then it came the second surprise was its 24x optical zoom, but still this is not everything at all, because it comes with an lense with an angle from 26 mm to 624 mm. One of the best you can get.
If this is not good enough. It is still a Nikon and not as expensive as the D90 or some near it. The P90 is perfect for private users who mind about the quality of their pics.
The only disadvantage that I see with the D90 is its RAM that is relatively low. It is important to have lots of RAM, I thing, but the camera has other things that compensate this problem.
The digital screen can be tilted from 90 degrees to 45 degrees up or down, it comes with an anti reflection treatment. Its sensibility reachs the ISO 6400, and very good feature to reduce noise between the modes of exposure has P / S / A / M.
I can tell you more about this camera, if this is not enough to convence you. The Nikon P90 can perform up to 45 continuous shots at 15 fps. It can take pictures in a macro focusing distance of 1 cm. You could make a very impressive picture of an ant with that feature. And to enhance the vitality of the images taken in difficult conditions it has a fast retouching function which offers incredible results.