The graphics are pretty awful on PS2. However, it sounds like it might be better than on your PC. But keep in mind you can't get Fatboy PS2s any more (retail anyway) and you need one to play FFXI on PS2.

A lot of my friends that were PC players tried it on Xbox and thought it sucked there as well compared to PC version because of how limited you are in adjusting resolution.

I dunno what to suggest if you aren't in a postion to upgrade. ><