On.
I like longer games. I prefer Marathon. Also, Raging Barbarians further helps slows the pace of games. Makes it harder to expand, and civs need to devote some early resources to military.
Also, makes things interesting since lots of civilian units get captured, which you can free. So this helps diplomatically - you can either free the civilians, or you can essentially "steal" workers without needing to declare war. Oh and barbarians help prevent pesky missionaries and prophets from converting your cities.