Firefox because it's one of the last browsers against the Chromium monopoly.
Also UBlock Origin is wayy better on Firefox, even before Google forced their version of Manifest v3 on all Chromium based browsers.
Honestly that would be a bad idea. This might actually push Mastodon into mainstream and makes it more accessible for non technical people. That also of cause means more content and I'm all for that. The only reason I haven't started to actively use Mastodon or Lemmy is because there just isn't enough content.
R