Fire Emblem is a damn good game that I'd recommend to almost anyone, even if they weren't into that kind of game. For my money, you can't go wrong there. I can't tell you which is better though, since Bravely Default hasn't been released in the States yet. I say, if you're playing the demo and loving it, you should probably go for it. Fire Emblem will always be there for later on down the road, right?
If it helps, there's a demo for Fire Emblem as well.
There is a Bravely Default demo as well, so might as well try both, @techhits
I just finished the BD demo, I dumped 6 and a half hours in....
I liked it
But I have only heard good things about fire emblem, still haven't made up my mind.