XI is an MMO, which means it's more expensive (Not to say that it's not worth it or a ripoff, but you gotta decide if the extra outlay is worthwhile), and that it is a far, far longer term investment than a standard game. The time it takes to get out of your starting lands in an MMO can exceed the time it takes to complete entire other games.

If MMOs are to your taste, and partying with other people is to your taste, you'll dig XI. If you don't like working with others, you'd want a different MMO, or a different game entirely. Whilst you can solo just fine in, say, City of Heroes or WoW, you're not gonna be soloing much of anything in FFXI, so be aware of that.