Brazilian Jiu-Jitsu (BJJ) emphasizes taking an opponent to the ground and using submissions such as chokes and joint-locks to win the confrontation or match. BJJ is based on technique and leverage, not size and strength.
BJJ is a great form of self-defense should the fight end up on the ground. It is also a great competitive grappling sport where one can test his/her grappling skills and it is a fun way to get in shape.
BJJ has been proven to be one of the most effective martial arts in the world.
Jeet Kune Do
Jeet Kune Do (JKD) was developed by Bruce Lee with the concept and principle of "Absorbing what is useful". If a technique did not work in combat, then it was discarded. When one thinks of combat they must realize that combat can cover the ranges of kicking, punching, trapping, and grappling. JKD teaches one to adapt to the combat situation or range by using all the weapons of the body; the head, hand, foot, elbows, and knees.
The JKD student is able to adapt to the street fight because JKD trains one for the realism of combat, which one hopes one never encounters. However one never knows when some street thug may try to put you or a loved one in harms way.
JKD is about expressing oneself and realizing what techniques work for you.