Multi-monitor support in 12.04/gnome3 is unbelievably good. There are tons of horror stories, that I've lived and that I've read, regarding multi-monitor breaking jut when it's most needed (presentation at conferences, etc). This has happened to me in the past.

Now, my system keeps track of my preferences per-configuration, so plugging in the monitor that I mirror display on automatically does mirroring, and plugging in the monitor I use as a secondary monitor automatically does that. Also, just plug and go for multi-monitor.

It's fantastically better than ever before. Anyone else noticed this?