WoW and FFXI.... are in a lot of ways similar... each has their pluses and their minuses. I personally liked FFXI better because for some reason I wound up with some good friends when I first started. Playerkillers can be tricky in WoW... which can be annoying especially at lower levels. THe inability to change classes freely is also annoying to me, because although I largely play mages or paladins, I like to test other things out because I'm an adventurer... as well as the cat curiousity killed.
I currently though play mostly Guild Wars... because its free online play, and I'm in university... so I don't always have money for monthly fees... Although.. I did save for PSU... but that was in the yearly budget.