What I most appreciate about it is how much it feels like a coherent world rather than just a bunch of vaguely related set pieces. It's not some standard set of fantasy textures or stories either: there's rich wood, gently reflective glass that looks like something from a banker's lamp, skies that are beautifully realistic, more npcs that have character (pardon the pun), etc etc. Like some others have said in this thread I can happily just walk around looking at things and soaking it all in.
It's also unabashedly romantic (in the larger sense, not just 'two people in love' sense). Some may find it a bit corny but when I'm in the mood for high fantasy I'm looking for something idealistic and enthusiastic, and that's just what FF XIV is like. You can pick at the mechanics of combat or classes or crafting or whatever, but it nails atmosphere and world building better than any other MMO, at least from what I've seen so far. GW2 probably comes the closest in terms of atmosphere/story/coherent world that has strong graphics to back it up, and I'm not ready to say which I prefer yet, I'll have to get to the higher levels in FF XIV before I make that call, but it's clearly had lots of love and care and attention to detail poured into it, so I'm looking forward to much, much more exploring!