I've been using the Slack, GIMP, and Darktable flatpaks on Fedora Workstation (which is GNOME based), available on flathub.org, for quite a while, maybe a year

I've been using the Slack, GIMP, and Darktable flatpaks on Fedora Workstation (which is GNOME based), available on flathub.org, for quite a while, maybe a year - without problems. I also sometimes use Okular which is a KDE app, and by installing it, the necessary kde.Platform runtime libraries were also installed and kept up to date by flatpak - works flawlessly. There's also a LibreOffice flatpak I have installed, and it seems like the flatpak update "deltas" are smaller than RPM updates, by quite a bit. I haven't used the feature yet, but supposedly there's a means of easily rolling back to a previous version in case an update has a bug the user can't work around. Rolling back RPM's can be non-trivial when there are many dependencies - it's way easier for me to do rollbacks of an RPM only based system by Btrfs snapshots which of course not everyone can depend on just for undoing an application update. So I'd say this is definitely an improvement from a user perspective; and it seems no more painful and perhaps a little less painful for packagers.