Anand, from the appropriately named site AnandTech, has gotten
his hands on an iMac G5 and an Intel iMac and took both for a spin. He spends lots of time in this very lengthy
review comparing the performance of the two, and time after time the Intel iMac is faster, but not mind blowingly
This review is extensive (have I mentioned that?), but it is well worth a read because there are many thought provoking gems in there. If you don't have the time to read it, Anand likes the iMac (though it isn't the computer for him) but he thinks that the iMac to get will be the next rev when we will (hopefully) see a brand new design that takes advantage of a much cooler running processor.