Well.it is if the Intention is a quite life.
I hope you're not assuming that the 'quiet life' is for the teacher's benefit but not the students'.
My initial posts on this thread were supportive of parents sending girls to single sex schools, and I am, but largely because of the sexual harrassment etc that they often suffer from boys, rather than because of boys' general poor behaviour (inside and outside the classroom. Because one thing I have noticed over the last few years is the massive deterioration in girls' behaviour.
Many girls are now displaying disruptive, offensive, aggressive behaviour on a par with the boys. I can honestly say that when spacing out the disruptive kids in a classroom these days, I'm just as likely to see well-behaved boys in between disruptive girls as the other way around.
The reason behaviour is often better at single sex schools is largely because they are often not 'bog-standard' comprehensive schools in 'bog-standard' areas. Admittedly I'd still say behaviour is almost certainly better in a girls' comprehensive than a boys' comprehensive, but I doubt there are actually that many of those around.
The two girls' schools I'll have worked at are havens of civilisation because they are a top private school and a highly selective grammar school. But yes, comparable boys' schools would be a little more boisterous (but still a lot less so than non-selective ones). The girls' comp I used to live near.... not so much of a haven!