The Leica M9-P has a CCD sensor type which is better than most comparable spec digital cameras that were released around the same time as it. Most digital cameras of a comparable spec and age to 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.
This digital camera's sensor type (CCD) is actually the best sensor type across all digital cameras of this type and age.
Across similar types of digital camera the worst sensor type is MOS.
There are a number of alternative cameras that have a CCD sensor currently available that you might also want to look at including cheaper digital cameras such as the Leica M-E ($4,927.99).