Conclusion
The previous generation is cheaper than these new cameras. The price gap varies from one retailer to another but is on average $100. Is this additional $100 worth it?

For the Kodak the answer is YES. The new camera body is definitively better than the previous one. It more pleasant to use, more accurate, and it includes twice as much internal memory. Pictures made with the DX7590 are equivalent or better (bigger and more detail) than the DX6490. And most of all, the DX7590 is clearly faster than the DX6490. Speed was the biggest disadvantage of this camera.
Choosing between the Z2 and Z3 is much more difficult. The Z3 has a nicer more refined body, a bigger zoom and a very efficient stabilizing device. With the zoom you will be able to take pictures that you would miss with most cameras including the Z2. With the stabilizing device also comes a new processor. We don’t like it very much as the accentuation effect increases sharpness but also the noise level at all sensitivities.
Along with the change in processor, Konica Minolta has also apparently changed the color processing. The new one is different… but not better. Pictures are still too warm.
Unless you use the maximum zoom most of the time, we prefer the Z2.
Z2 or DX7590 ?With a better macro mode and LCD screen reactivity the Z2 is $100 les expensive than the DX7590. On the other hand, the Kodak screen and sensor are bigger and the camera body quality higher. All in all, the DX7590 wins this test but just by a few points.