Billed as part 1 of a trilogy, strictly speaking, it's more of a three-part mini-series. This first part is a little slow, since it is establishing the characters and setting the story. However, the whole trilogy builds up into a nice little fantasy which does have a genuine Arabian Nights feel to it - albeit with a little early technology thrown in.
It maybe not be quite up to Studio Ghibli standards, but it's perfectly watchable. It is suitable for all ages. There is no gore, nor any gratuitous sexualisation of women, which amines can occasionally be guilty of. The English dubbing has been done very well (so well it won a couple of awards) and flows very naturally, unlike some amines where the dub can feel a little awkward.