[smabie]

I would say a rock solid runtime with a focus on consistent performance, a nice C ABI, and low memory usage. Haskell suffers in non-trivial use cases and the is very hard to profile. Laziness has never worked correctly and in my view is a big mistake. Laziness is a dead-end, despite all the elegant code it allows you to write.

Also the tool chain is miles better than Haskell. I'd even say that the build/package management and editor tooling is some of the best of any language.