Not being a fan of Bravely Default myself I can only go by what I've been hearing and that Fairy's Effect is pretty good fan service for those who have enjoyed the full-fledged games on 3DS and who know what they're in for with the whole social RPG thing. The bummer news is that there's been no indication that Bravely Default Fairy's Effect will be localized outside of Japan, and given that Bravely Default: D's Report never made it out West, I'm kind of doubting this one will either. That said, anything can happen and we'll keep our ear to the ground for news of the game heading stateside, and I'm guessing Shaun will pick this one up at some point and be able to give you all a much more expert opinion on the matter than I can. If you're feeling adventurous though, it sounds like the game is easy enough to navigate without understanding the Japanese, so if you want to give the free download a shot you can do so via the link below.
Japanese App Store Link: (Universal)