If you are asking best against some punk who picks a fight you are talking street fights.
I never recommend going to the ground in a street fight if you can help it. If this punk has a friend with him and you hit the ground his buddy is gonna stomp your face in.
I would say take a striking art, like MT.
Though personally I would recommend taking both. Being well rounded, in case the punk tackles you, is never a bad thing.
Isshinryu Karate 2nd degree Black belt.
Neko-Ryu Goshin Jitsu 2nd degree Black belt.
Jujitsu 2nd degree Black Belt.
Isshin-Jujitsu 2nd degree Black belt.