I've been playing this game since last week now (well, whenever I can actually log in) and about the best I can say is it's a competent WoW clone.
There's nothing outright bad about the game and it's entertaining enough, but there's nothing special or memorable about it either. I admit I'm only level 16 at the moment (mainly because I can't log in when I want to) so I haven't experienced everything, but I really don't see a reason to pay a monthly fee for the game once my free trail goes away.
Massive kudos to SE for making FFXIV into something playable and even something decent, but I haven't seen anything that makes me want to pay a monthly fee for this game. I want to pay even less when I just spent the last 10 minutes clicking the screen trying to log in only to eventually be met with the can't populate character list error and have to give up.
I'll expand a little-- FFXI was a different MMO. You set out with a purpose and did that. The game had its flaws but it did many things to make it stand apart from everything else out there. That is why it was as successful as it was.
FFXIV tries to be just like WoW with a Final Fantasy flavor. They aren't doing anything risky and just looked at what every other MMO that tried to be like WoW and copied them. It's a better game for it, but it's nothing special. I haven't really had to interact with a single person, I just log on, do quests until I'm bored, and then log out. In FFXI I had to be social and get help and help people from nearly the get-go. In FFXIV I might as well be playing a single player game.
I'm enjoying myself for the most part and, again, it is a well done game, but there's no reason to play this over any of the other no monthly fee MMO's out there.