The Leica D-Lux 3 has a CCD sensor type which is better than most cameras of a comparable age and type to it. Most similar spec cameras that were launched around the same time as it have a MOS sensor type. CCD sensors produce high quality, low-noise images but consume a lot more power than CMOS sensors. CCD is the most common image sensor type used in digital cameras.
A CCD sensor type is in fact the best sensor type amongst all digital cameras of this age and type.
The worst sensor type amongst similar types of camera is MOS.