Originally posted by Dave the Great
Yes, you would notice a difference. Not so much going from 680k to 1.333MP ( some more lines of video resolution, but really the extra pixels are for stills), but the size of going from a 1/6" to a 1/4" makes a big difference in light sensitivity.
However, since you already own a ZR 20 and you have already purchased the ZR80, you shouldn't second guess your purchase. I am sure the ZR80 is a good cam. Plus, it was only $331. And you are familiar with the Canon nuanances, since you owned one previously.
I hope you are right. I could have purchased a sony with a 1/4" for only 417. I just did not like the touch LCD. I was afraid it may be more prone to breaking. It may not, I just thought it would be.
My ZR20 was almost three and a half years old, so I imagine the ZR80 will be an improvement.