The PowerShot SX420 IS has a CCD sensor type which is better than most bridge camera digital cameras that have been available for a similar time to it. Most recently released comparable spec digital cameras 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 actually the best sensor type amongst all recently released similar spec cameras.
A MOS sensor type is the worst sensor type across comparable types of camera.