I tested both browsers for several weeks in a university fingerprinting study (I wanted to leave my fingerprint rather for academical research rather than at fingerprint.com).
The study measures the browser fingerprint based on e.g. navigator, audio, canvas, screen, plugin, connection, WEBGL, mathematical constants and much more.
The study determines whether the site:
- has seen this fingerprint before
- if you are the only participant with this fingerprint and
- if you can be tracked uniqueliy over time
In the categories "seen fingerprint before" and "can be tracked uniqueliy over time", Brave regularly performed better in my case: Vanadium was trackable over time and could be assigned to my previous fingerprints which was not the case with Brave.
Better to do your own comparisons than listen to strangers on the Internet: https://browser-fingerprint.cs.fau.de/?lang=en
So for most things I use Brave, when I open sites where I'm more concerned with security than privacy I use Vanadium.