Obviously the most interesting vs fight would be between Bruce and Brandon Lee!
So, why do I not see anything about such a topic mentioned here?
I believe that for the most part, people interested in vs fighting are afraid to even approach the topic of Bruce vs Brandon in discusion.
Brandon didn't seem to deliberately showcase his speed and power the way Bruce did, while if one pays attention one will note that Brandon was very, very fast and powerful.
Brandon also had much more time in his life available for Martial Arts training than Bruce.
Therefore, with all things being equal, Brandon would hold the experience advantage given more time to study and train in his short life vs Bruce.
Brandon was after all tought by his father who just so happened to be Bruce!
Speed and power aside, Bruce was odiously ferrocious, while Brandon was very fluid and loose.
It's like looking at both sides of the same coin at the same time.
Given time, Bruce and Brandon could train to accomodate fighting the other.
Much like in Greek mythology with the hound fated to never lose it's prey and the stage fated never to become prey, Bruce vs Brandon or Brandon vs Bruce would end in a frightening stalemate!