Both cameras use the same engine (processor), so you can expect equal performance from both.
The ZS5 has more optical zoom and is slightly larger and heavier.
If you want more control of your camera, the ZS5 has the important manual controls.
The ZR3 is strictly point & Shoot, with mode selection.
I need a new camera to shre with my wife. I think I am down to either the Panasonic ZR3 or ZS5. Both seem to have very good reviews. While similiar I'm not sure what which to go with. Any opinions?