Which extension are you using? I use Mate and found a Gnome extension that was known to be unreliable and indeed did not work...

I agree the restart is a minor issue, as is the menu bar showing by default, as is the bookmarks bar being always/never there (rather than the more sensible Chrome behavior), as is the interruption of my workflow when Firefox decides to check for updates when I start it, as is the relative laggy UI, ... But these issues add up to a worse experience. Worse by enough that despite wanting to avoid Chrome, I came back to it :(