Personal preference I guess. I’ve tried Firefox many times over the years and always ended up going back to other browsers. I find Firefox doesn’t render some pages quite right, the user agent stylesheet is odd, and the UI is less streamlined. Performance also used to be a problem although I hear it’s caught up now.
I used to be a Chrome user but now I prefer chromium based alternatives like brave and edge (which incidentally, uBO will keep working on). Chrome is still required for work, but uBO change won’t be an issue I think, there are plenty of other ad blockers that will work with MV3