If your only consideration is image quality and price, then I can see why the z7590 would make a good choice. I guess it depends on what you are going to use it for. And everyone has different preferences.
I find it hard to rationalize that the z7590 would be abetter pickthan the P850. Granted the z7590 is a greatcam with good reviews - but it's over 2 years old - AND limited.
They are truly three different cams. All withvariations in flexibility and features.
However, no matter what the reviews tell you, thep850 does have more capabilities and featuresthan ANY of them.
2.2 in LCD, flash hotshoe, 640x480video at 30fps with zoom, OIS, manual focus, histogram....to list a few.