Just downloaded it (1867 blocks ~233mb).
It...feels like a legit return of Final Fantasy...lots of classes to figure out & mix(!), art-style & effects, orchestral music, turn-based//random encounters, fixed camera, I've entered two caves & died on the first round of battle. This game was already a pre-order, but now I can believe it.
I almost didn't want to get the demo, and let the game give a full initial impression...but I couldn't help myself.
There are no spoilers to the demo, it's more just a few simple item-quests and town/world-map run. Experience doesn't transfer, yet some items and streetpass stuff does. I may just leave it at a 1-time play and wait for the real thing now.
...anyway, the demo is out now.