The D-Lux 4 is identical to the Panasonic LX3 but costs 2x as much. The only little difference is in the firmware of each camera. The hardware is the same, and image quality should also be the same if you shoot RAW or nearly identical if you shoot JPEG
The LX3 is well worth the money. It's one of the best pocketable cameras out there today.
Interesting! The more I read about the D-Lux, the more I think it's not a real Leica.