Actually, resolution wise, our zaurus is pretty good though the Nokians 770/800 should compare very well to it since it is of higher res, though bigger screen. So we should really be talking about dpi here.
Readibility wise, outdoors, CG LCDs are crappy. I've not seen the 6000 before, but my previous T3, which sports a transflective screen from sony, looks much better in outdoors.