I added 'hide top bar' and that maximizes the browser window and 'bottom panel' which moved the whole thing to the bottom - hide top bar continued to work as well.
As explained in the article in that link in my previous post you have to install gnome-tweak-tool first (sudo dnf install gnome-tweak-tool). From within that tool you can install many extensions (but you have to start the tool anew to make them visible/configurable): The panel on the right side is "Workspaces to dock", the panel at the bottom is "Dash to dock" (you can alternatively place it at the top, at the right or at the left). No, that's a setting in the tool itself, also the maximize/minimize buttons. EDIT: Another useful article is https://www.linux.com/learn/tutorials/781916-easy-steps-to-make-gnome-3-more-efficient
Well, KDE 5 is almost complete, so you won't find a lot of bugs. Personally I tested it 2 days ago and it all worked fine. But I don't want to use KDE anymore. MATE has everything I need, is lean, light, and pretty. Not to mention menus in the right places hehehehe
FWIW, I have 2 Fedora installations with Gnome and Plasma 5 running in VMs and both are absolutely stable. I particularly love its delta updates which often drastically reduce download size. E.g., today's updates for the KDE version contained 60 packages with a download size of 76 MB which was reduced by 86.1 % to merely 9.9 MB!!! Wow!
Yes, I personally agree that Plasma 5 has become rather stable in the meantime. And if you install a new distro with it you shouldn't run into problems. However, the transition from KDE 4 to Plasma 5 caused a lot of trouble - just look how long the KF5 & Plasma thread in the Arch forum has become. One reason was different configuration files locations.