Miyazaki-san fans will be happy with this one I think. Reviews have given it high marks, but I wouldn't count it among his best. The animation is excellent as always and does look extremely good in HD, especially considering it is hand drawn. Color is very vivid and the PQ is super clean. The audio is quite good as well. The story is good, but not spectacular. For those who don't know, it is a sort of reimagining of The Little Mermaid. It departs from that story quite a bit, and though entertaining as always with Studio Ghibli films, it doesn't quite have the same feel of a Howl's or Spirited Away.
There are a ton of extras on the disc too, a number of trailers indicating that a number of Ghibli catalog titles will be coming to BD. There is a "World of Ghibli" map where you can click on various animated characters and it takes you to various clips from that film. I already saw the announcement that Naussica of the Valley of the Winds will be released soon.
Miyazaki fans will likely pick this one up. For everyone else, recommended rental (I got it from Netflix).