I posted this in another thread. I played FFXI for a while and quit as lvl67 pally (and some other high lvls jobs). If you compare WoW to FFXI:
1) Leveling is MUCH faster in WoW. Actually sometimes you don't even notice it, because the quest system is awesome. You do the quests, do this, that and the boom - holy damn, another level :)
2) In WoW you spend 85% of time doing something fun, while in FFXI you spend 80% of time getting group together, travelling, etc.
3) You have a choice in WoW. You can grind, like any other MMPOG or you can quest. Both choices can be done either solo or grouped. Only time you are FORCED into a group is when you want to do elite instances. Grouping is very flexible though, so no perfect set up - all classes are saught to, as long as there's a balance of healer/dmg (healer is not just a priest, but druid, palladin and shaman as well).