Chokes for me. Even though I am very inexperienced in the gi, my chokes have gotten me out of trouble when I helped a guy who confronted some other guys for smoking on the tube. He was gonna take a kicking as it was two against one so I helped even the odds. I choked one of those guys good. Chokes are very much my 'go to' move when it comes to self defence.
BJJ Black Belt
At my school O-Soto-Gari onto concrete was very effective.Especially because the gripping part of it stops the pre-emptive headbutt of the attacker
which was the weapon of choice in London Schools in those days.