[X4U] which G5 iMac model is best?

[zapcat]

I'm looking at G5 iMacs, now that everybody is unloading so that they 
can upgrade to whatever new Intel Mac has caught their eye...

I roughly know about G5 iMacs, but not sure if there's a "best" model...

is the 2.0Ghz significantly faster than the 1.8?
do any of the screens suffer from sneaky marketing, as in the case of 
the aluminum iMac "millions" of color deception by apple?

thanks for contributing any thoughts/experiences.

zc