FFXI has an excellent job system. Unlike other games, if you try a job and don't like it--or get it to 75 and are done with it, you do not have to make a new character. You can change jobs at will, and skills you learned at other jobs carry over to the new job. Each job has a skill cap for each level, so having a level 75 thief does not mean you can make a level 1 ninja with 200+ evasion, but your evasion as ninja will be capped until you reach 75, as thief has a higher evasion skill than ninja. If you level an axe warrior, the axe skills you learned as warrior will serve you well as beastmaster. Secondly, by mixing and matching jobs (i.e, changing your support job,) you can radically alter the role you play--a samurai with warrior sub is an all-out DD, while the same samurai with thief sub can help keep hate on the tank, or with ninja sub can take more hits via the use of shadows. Also, FFXI has jobs that no other game has. I haven't seen another job with a samurai class, or blue mage, or red mage, or even a bard class that is as strong as FFXI bards. Yes, D&D based games allow multiclassing, but you can't switch class at will like you can in FFXI.