It's pretty much a straight-up hard sci-fi tale that falls in line with what you might expect from, say, Niven or Heinlein or Brin. Also the story is emblematic of the type of themes that were being explored at the time, as the grand hope of space comes crashing against the hard realities of humanity's foibles. And it's really three parts of a story that are interwoven together, across a span of about 400 years.
There are some nitpicky details to the story setup (which comes with the territory when you are dealing with the harder edges of SF). And also, hints of a much larger, broader universal story out there -- but clocking in at just under an hour, there's only time to focus on this one slice of that larger universe.
When I say this comes up lacking, it's because the manga itself was a masterpiece of artwork and storytelling that would be hard for *any* adaptation to compare. Hoshino's artwork is crisp and clean, and that translates into animated form somewhat unevenly. And the animation quality is a bit on the sub-par side, relying heavily on pans-and-scans of grand backgrounds and landscapes and less on movement. Takeuchi does his best, but it's a tall order to capture the grand scope of the manga.
Taken on its own, for someone who is unfamiliar with the manga, it's just "okay". But if you have the opportunity, choose the manga instead.
