It turned out that the bug preventing a useful two monitor setup to survive a reboot is likely not related to gnome but rather to the Xserver and Xrandr and the like, but it looks like I'll stay with Xfce4 rather than going back to gnome.
I am used to certain configurations for many years that I do
not want to unlearn for no good reason. When I set up gnome-3 last
June on my Ubuntu 14.04, it was a real pain. One of the silliest
things I found was that standard usage of
is not working anymore. Neither just have the file nor adding an
explicit call in
~/.xprofile seems to work anymore. I
had to add an
xmodmap.desktop file to
~/.config/autostart with the nasty side effect that
after a hibernation the keys are not restored. No idea why it
works in Xfce4, but it does.
Also many other tweaks I like where just a pain to figure out how to do in gnome-3. Having 3 desktops (or whatever they are called there) and just drag a window from one to the next — I could not get it to work. Window title bar buttons where they belong. They were on the right since they exist and they could as well be on the left, ok, but what is the point? Yes, I figured out how to move them in gnome-3, aaargh, but what a dig through the web.
Then the Jobs'ish way of having the main menu at the top of the screen. How silly is this on large screens? And it is completely useless with focus-follows-mouse. Just try it with several windows open not covering your whole screen. Again it took many searches on the web and many configuration steps to convince all applications not to use it.
Compared to this, there was much less I had to tweak in Xfce4 and, even more, there is a large menu entry called settings where one can just try out things. In gnome the settings are dumbed down. Why? And finally it felt like Xfce4 has more accessible documentation on the web then gnome, which also makes it easier to tweak everything.
This is my completely subjective opinion after going through the two configuration tasks to get everything like I like it. Others may have other experiences.
I was afraid the gnome way is the 'modern' way and I have to adapt. Well, not yet, it seems. Xfce4 to the rescue.-)