I started out in TKD. After about 5 years I got fed up with the "take-your-dough" system I was in (good instructor, terrible system) and left. Having discovered that it did very little to help me in street fights as an LEO was another reason. Great exercise, and some good basic how-to-hit/where-to-hit instruction, but most of that was learned early on. Most of the stuff I've seen taught after green belt is fluff and looks-good-in-forms-and-tournaments sort of stuff. 360 jump front kicks, high spinning side-kicks, and such are great for getting your butt kicked in public.
I got into some "corporate martial arts" for a while. Those are police/military aimed systems that fall under various "Defensive Tactics" labels. PPCT is one of them. I was an instructor in that for a while. It was very comprehensive, but covered, IMHO, way too much way too fast and not often enough for the officers to maintain their skills. It was also very expensive for a small department to maintain certifications (company would change one paragraph in their manual and to teach a class we had to order new ones for every officer at $40 to $60 each).
Then a Japanese based jujutsu school opened here and I was hooked. I didn't ask for a trial class, I didn't sign up for a week. I signed up for a month figuring one good or one bad night would not give an accurate example of the art. That was ... wow ... almost 12 years ago. Through that system I've also studied and ranked in Aikido and Judo. I also, in a brief moment of madness worked up yet another TKD black belt rank with the not-so brilliant idea of adding that cash cow to our system. Even though we were cheaper, our area was just too saturated with TKD for a new school. Then, if they saw what the jujutsu folks were doing, they wanted to do that instead, LOL.
What I've found is that grappling-bases systems designed for warfare (i.e. Japanese Jujutsu) work the best for real street fights. They also offer a lot of force options, from simply evading an attack and escaping, to dropping an attacker with either a little or a lot of harm, on up to crippling/killing techniques. Often it's only a minor variation of a technique that makes the difference between how much force is applied.
Pure striking arts means the only tool in your toolbox is a hammer and not every problem is, after all, a nail. Pure grappling will have you wind up on the ground when that might not be the best option. Japanese jujutsu combines strikes (atimi-waza) with grappling, choking, throwing. Not all grappling is ground-based. In fact, we stress NOT going to the ground unless you have to, but that if you wind up on the ground (and I'm the clumsiest human being you've ever met -- sports doctors love me) that's cool, you can take care o'business, and get back up to deal with other attackers quite quickly (or fight from the ground if the situation dictates).
Judo is, IMHO, one of the coolest martial sports out there. The Ju-waza (lifting, pulling, pushing, close-in techniques) were taken, rules were added (a LOT of rules lately), some safety concerns were addressed, and a point system was established (Pre-WWII judo is very close to actual Jujutsu ... modern Judo ... not so much). Certainly you CAN fight with Judo, but since it, like BJJ is concerned with mat-based techniques, points, avoiding points (i.e. taking bad falls to keep opponent from scoring), etc., the muscle memory you develop will be more suited to the competition ring than to the street.
Aikido is ... beautiful. The Aiki-waza (arms-reach, big movement, big fall techniques) is taken from jujutsu and made into sort of a moving meditation with a willing partner. It is not for fighting. Sure, sure, after several years and a few dans of rank you can probably handle yourself okay, but that is not it's intent or focus. Self-Defense Aikido is basically watered down jujutsu. We train in aikido to soften up or jujutsu. We have a lot of good ol' boys who just can't quit using muscle (even one tiny guy who simply has no muscle to speak of). Well using strength RUINS aiki-waza an aikido techniques. Aiki-waza is the higher form of jujutsu, is much harder to learn, and should be the focus of anyone over 40.
Hmm ... so to answer the OP, I'd have the say, Japanese based Jujutsu. But you probably already figured that out, eh?
