I tried using the globals, but it does not have much affect, so I don't think ESM has that much to do with it, see results here: https://github.com/grissius/jest-is-a-rude-needy-clown-and-e...

The benchmark covers several different scenarios, and memory and time efficiency leans more towards Jest (which is already pretty bad as it is), so I don't think it is fair to declare "A blazing fast". The project looks promising (appreciate ESM and TS support), don't get me wrong, but speed is not its strength.