I'm level 19 and...despite my best efforts, I'm kinda hooked. I hear though that the story quests stop at level 20 in the beta
I spent the day doing the 3 first quests I've encountered that required a party. This is where an MMO's fun can really be luck of the draw based on the party you get. Fortunately, I lucked out got a pretty great party and we ended up sticking together the whole day, it was fun. Also, the dungeons were neat too, and had a couple little quirks to make them interesting.
It's still nothing hugely revolutionary for MMOs, but it's a solid one a nd the Final Fantasy theme helps
I love heaing the victory theme on level ups, community events, and dungeon bosses. And I've also heard the FF Main Theme, it's got a great chocobo theme, and the dungeon theme is a cool battle track that uses the Prelude.
Also it's fun knowing just about everyone playing is also an FF geek. In the dungeon today the Healer used our Limit Break (a party shares a limit bar and what it does depends on the role of the player who uses it) and it was Healing Wind. To which he/she cried "I'M AERITH YO!"