Rex Sorgatz wonders what sort of robots we'll build, R2-D2s or C-3POs.
R2-D2 excels in areas where humans are deficient: deep computation, endurance in extreme conditions, and selfless consciousness. R2-D2 is a computer that compensates for human deficiencies — it shines where humans fail.
C3-PO is the personification of the selfish human — cloying, rules-bound, and despotic. (Don't forget, C3-PO let Ewoks worship him!) C3-PO is a factotum for human vanity — it engenders the worst human characteristics.
I love the chart he did for the piece, characterizing 3PO's D&D alignment as lawful evil and his politics as Randian.