They're similar in terms of how advanced they are. I find Nim preferable, personally, and has a pretty excellent batteries-included standard library, as well as

They're similar in terms of how advanced they are. I find Nim preferable, personally, and has a pretty excellent batteries-included standard library, as well as robust tooling and third party library support. That said, I'm biased, and haven't used Crystal for a couple years. Anecdotally, I see more uptake of Nim than I do of Crystal, but again, I'm biased and it's likely because I'm looking for it, rather than it being a fact of the world.