Here is a look at their specifications, side-by-side:

The quality of the images are just about equal on these two camera.

Something to think about:

The shutter lag on the Sony W70 is 0.3 second
The shutter lag on the Nikon P4 is 1.0 second

That shutter lag on the P4 is too much for such a new camera, and will cause you some dismay.

The P4 is also lacking a viewfinder, and may result in some problems of trying to take a photo in very bright sunlight (which will wash out the image on the LCD).

The P4 has optical image stabilization which some people like.
It also has one more megapixel.