The IXUS 180 has a better sensor type than most comparable spec cameras that are a similar age to it. This camera has a CCD sensor type, whereas most digital 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 compact camera digital cameras that are a similar age to the IXUS 180.
A MOS sensor type is the worst sensor type across similar types of camera.