Having switched to Zen Browser, something I miss with Firefox was its stability. I find myself looking up Zen browser bugs and workarounds too much. This is the 2nd or 3rd time I’m downgrading Zen versions due to a bug in the stable version, I never had to do so during my years on Firefox. Devs on Github making an app on their free time have can’t spend as long on QA as a multi-mullion dollar organization.
I downgraded Firefox once last year, but after the next major version a couple weeks later, I was able to upgrade again. Never had to downgrade it before that, though.
I forget why, though. I think it was a pretty niche issue.