Of course, you could say One Piece has reached 800+ episodes and its world-building is extensive. However, the scale of Legend of Galactic Heroes is much greater, and could be seen as potentially infinite.
The story is one of anime's greatest, focusing as much on past events as present ones, and both, are equally important in the context overall. The scale of the space battles (which happen often) are truly impressive, with up to tens of thousands of ships in each one.
The art evolves over the ten-year (yes, you read that right) production, but so gradually as to be barely noticable in most cases.
The characters are brilliantly defined, most standing out with flaws and personality quirks which become increasingly apparent as the series progresses.
If, however, paragraphs of subtitles and occasionally graphic deaths aren't your thing, you'd be better off elsewhere. But if you want to watch one of the most engrossing and impressive anime ever made, this is for you.
