The Pixpro AZ251 has a CCD sensor type which is better than the MOS sensor type found on most similar spec digital cameras that came out around the same time as it. 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 in fact the best sensor type amongst all cameras that came out around the same time as the Pixpro AZ251.
The worst sensor type across similar types of digital camera is MOS.
There are a number of alternative digital cameras that have a CCD sensor currently available that you might want to look at including the Fujifilm FinePix SL240[plb_1349973_price] which has better reviews; or the S4500[pl_1353342_price], or the FinePix S4200[pl_1353343_price] both from Fujifilm which is cheaper.