IIRC HVIF is designed to render in one pass as well targeting to be both small and fast. It also use non-standard floating point, to be even more compact. And has more than two level of details. So guessing HVIF is a lot better except for tooling outside Haiku :)
Here is an article from 2006 about HVIF: https://www.haiku-os.org/news/2006-11-06_icon_facts/