Switching users is not reliable; when switching users, often when returning to the first logged-on user, the computer ends up a blank screen and I must turn it fully off with the power button. Success is somewhat likely if a minimum of programs are running. I prefer a complete log-off, as it is.
Because there is a lot of screen flickering generally during these operations, I have taken care to make the monitor settings identical. But this doesn't help.
I use Ubuntu Lynx with Gnome desktop. I have an Nvidia 3DForce FX5600, set to 1280x960 at 60hz; displayed on a ViewSonic VG2021m. "Desktop effects" is set to lowest/normal (solves bad screen-flicker issue). The gnome-power-manager app is removed because it caused problems when logging off.
Will re-install fresh with Meerkat 10.10 and update this post when I see what I've got.