The 1800FP uses the BGR subpixel geometry, not the far more common RGB geometry. MacOS X's subpixel font smoothing is written to support only RGB panels, which is why you're not happy with the way text looks. If you use the MacOS X setting for CRT font smoothing, it'll look better (but not as good as some other panel).
WinXP was also this way until SP1, which added support for BGR panels to it's font smoothing algorhythm.
I have one of these displays on my PC.