...but hardly the best either. Speaking as an anime fan starting back in the 80's, I thought I should add a few comments based on my own experience with the movie.The visual images are pretty darn good (especially in the imagination sense) for anime of the period. Enough so that I chased down this movie years later so that I could finally see it in a subtitled (preferred) form later and understand the story.
The story does have many weaknesses, as previously described, which can make the movie a miss for some folks and indeed some expository pieces can be painful in the dubbed version. However some parallels can be drawn to the classic Seven Samurai style plot, and can be enjoyed as an adventure story rather than endured and studied as a piece of critical work.
That is certainly an unfortunate thing, since better developed and written, this could have been as good as Akira, since some of the same kinds of elements are there. But seen as a movie that did set the stage for movie's such as Akira, it does have it's place.
As such, it's on my shelf and I like to watch it every few years, but you should definitely consider it a rental until you know if you like it or not.
Technical comments:
* Dubbing, as is usually the case with anime (with a few noted exceptions such as Monoke) is very poor and shouldn't be endured. If I understood more Japanese, I might feel different, dunno.
* The DVD has problems working with some DVD-ROM software (computer based watching). It worked fine in my PS2 player, but a cautionary note for PC-DVD users.