I mean, based on the claims and the benchmarks, it seems to provide massive speedups to a very popular tool.
How would you define "quality" in this context?
Written so that it's easy to maintain, well tested, correct in its handling of edge cases, easy to debug, and easy to iterate on.
High quality code isn't just code that performs well when executed, but also is readable, understandable and maintainable. You can't judge code quality by looking at the compiled result, just because it works well.