At a grocery store in Kyoto, I bought what I thought would be a bag of mango pudding KitKats, but I forgot to read the front. If I had, then I would have known that this bag was half regular chocolate, half mango. It was kind of a let down when I got home.
But in any case, this KitKat has been reviewed a few different places (Japanese Snack Reviews and Jen's KitKat Blog, for example), but I thought I might as well throw my opinion into the pile as well.
The KitKat has a strong mango smell and it reminded me of mango sherbet. The flavor was very bold and fruity, and definitely mango. It was sour and tart, but it still went pretty well with the white chocolate.
It was different from other KitKats I have tried in the past, and definitely one of the best fruity KitKats I've ever tried. It was very sweet, but I am a big fan of mango, and the flavor was fairly authentic overall (for a KitKat).