I don't know if this is because of Snap, but my work Ubuntu desktop sometimes takes ages (relatively speaking) to open a new Firefox window from the context menu of the dock icon, or whatever Ubuntu calls its version of the Gnome favourites.
That's the only practical gripe I have with their Firefox packaging. Since my workflow includes opening a new browser window quite often, it's an annoyance when doing that sometimes works fast and sometimes it takes a random amount of time.
I don't know for sure that that's because of Snap but it doesn't happen on my personal laptop with Fedora.
I have also noticed the issues with the Gnome shell integration and KeePassXC integration but I can live without those.
Snap-Firefox is noticeably slower on startup for me as well. After upgrading to the latest Ubuntu where snap-Firefox is default, I completely uninstalled snap and all packages then installed from a PPA.
Everything is better and smoother now.
Ubuntu is great but snap continues to be the worst part about using it.
Edit: Instructions for removing snap completely and switching to non-snap Firefox as well (not my site):
It isn't just an issue with Mozilla or with snaps. The flatpak version of Mozilla suffers from many of the same issues. I avoid snaps and flatpaks for any desktop software. Each introduces bugs and/or annoying limitations by trying to sandbox applications which were not developed with such a model in mind.
Yeah I don't see the need for this tech anyway in 95% of the cases they use it for. Sure, packaging is complex but distributions have become really good at it. It's a solved problem. And for the security parts there's better solutions like AppArmor. For some exceptions it could be useful but not with the ubiquity that Ubuntu uses snaps.
In any case I really wish Ubuntu would stop this "not invented here" nonsense and drop snap entirely (and use flatpak only for the apps that really need it).
After Mir, upstart, unity I thought they'd have gotten enough of a reality check but they're at it again. And they sandbox way too many packages that don't even need it. Even some golang command line tools which don't even have any dependencies (they're in go and thus statically linked)
The security boundary thing breaks smart cards. Had to jump through unpleasant hoops to keep my Firefox profile after upgrade. Plus, patching now is two separate things instead of one. Different version of packages are in two different repos that I now need to search.
Literally just broke a bunch of stuff and gave me nothing in return.
That's the only practical gripe I have with their Firefox packaging. Since my workflow includes opening a new browser window quite often, it's an annoyance when doing that sometimes works fast and sometimes it takes a random amount of time.
I don't know for sure that that's because of Snap but it doesn't happen on my personal laptop with Fedora.
I have also noticed the issues with the Gnome shell integration and KeePassXC integration but I can live without those.