They're WebKit-based and for MacOS/iOS/iPadOS only, so they don't get max points for browser diversity, and I can't run it on my Linuxes. As far as I understand, they plan to target more operating systems, and to target the most popular add-ons for other browsers.
I'm not satisfied until it supports an OS-agnostic (non-sucky, no thank you 1Password) password sync and works on Linux.
I hope they'll grow into a worthy alternative to Firefox, because Firefox is going down.
One review of alternatives here scores Waterfox at the highest, but I think I prefer if a company is behind it:
> Until, of course, we get the modal of death: "For best and safest experience, must view on officially certified Google Chrome (tm) (r) (diaf)."
Which will probably happen super fast (unless antitrust regulators get involved) since Firefox's market share is in the toilet and continuing to drop.
Firefox also can't push too hard, since (IIRC) pretty much all their funding comes from Google.