Because of how well it tells a story. The MSQ is one long continuous chain from the moment you first login at level 1, all the way to max level. And it's brilliant. No other game in the West - that I know of - does that. In SWTOR, you have your class story which goes from 1-50, but that's it. After 50, it's the same story for everyone.
I find myself fully engrossed and engaged in this game. I think about it even when I'm not logged in playing it.
Then I come to these forums and see non-stop complaining about everything. And as someone coming from WoW and other Western MMOs, I truly wonder if you guys know how great you have it. Honestly.
MMOs in the West are having a tough time. Mostly because it's all about ilvls and/or PvP ratings. FFXIV is about the story. And that's rare these days.
Hope you guys recognize that in between your constant complaining.