http://www.anandtech.com/mac/showdoc.aspx?i=2685
Just finished reading it. It's a pretty through review/comparion of the two iMacs. I was surprised (to an extent) at the iMac Core Duo's far lower power usage (then again, it is a mobile chip). As a testiment to the G5, however, it did perform overall better in Anand's tests than the "Core Solo 1.83 Ghz" (i.e. Anand disabling one core).
I guess it's good for Apple/Intel's sake that Apple never released a dual core G5 iMac, or else the only thing going for the Intel iMac would be it's greater performance
per watt (but overall having lower performance).