Unfortunately it seems to be slightly more than twice as slow. On the plus side, that is some justification for the existing optimizations.
I didn't delete some, apparently, and an internal struct had to be made public to get its benchmark to work.
It has a ton of great features[1], including stronger statistical signifance tests, making comparisons to previous or baseline runs, nice plots, and being able to be run on stable. 1: https://bheisler.github.io/criterion.rs/book/
Brandon W Maister