I know very little about him really. I've got his book "Tao of Jeet Kun Do" and it's a beautiful book, and interesting to see how he picked what he thought were the best bits from various styles (such as Muay Thai, Western Boxing, Kali, Wing Chun, etc"
My honest opinion is that whilst he was undoubtedly a very good martial artist, at the end of the day he was an actor, not a pro fighter, and I can't see him faring well against a pro combat fighter. I may be completely off the mark with that opinion, who knows.
I'm sure I read that he had a few illegal street and rooftop fights when he was in Hong Kong.... winning some and losing others. Again not sure how true.
Im a great believer that the "hard" martial arts and combat sports, such as Muay Thai, Boxing, Kyokushin Karate, Judo, and even to a small extent MMA, are where the very best fighters will be. Not because those styles are any better, but they can be trained full force, day in day out, on pads, bags, and against live sparring partners.
I think the traditional martial arts suffer because their moves are too "deadly" to be practiced at full power against a resisting opponent.
When I did Muay Thai, my gym was also big in Kali (the traditional Filipino martial art), and it was scary to watch them practice knife fighting, stick fighting, and trapping etc. I had a go and it was so difficult. Obviously a knife fighter who is practiced in the art will be pretty unstoppable, but I guess that's a special case. But whether a traditional martial artist could stop a fully trained "fighter", I have some doubts there.
Hope to not offend anyone who may be reading this and a traditional martial artist...