Bruce Lee or
Jackie Chan? The answer, in my opinion, amounts to something like a
personality test-- in that it's informative about personal preferences.
Martial artists, while violent, are not perceived as having devoted their lives to
violence; they are martial artists, not artistic
mercenaries. So in preferring one
martial arts style to another, we are really expressing our artistic
taste.
The dichotomy here is similar to the choice between cats and dogs. Bruce Lee was catlike, with taut, lithe, graceful snapping movements. One of his goals was intensity; another was self-expression. He both needed and used martial arts as a way to express himself, and he viewed himself as intense. Furthermore, he was admittedly cocky about trying to define a personal style with which he presented himself as intense.
Jackie Chan, on the other hand, appears to use martial arts as an expression of his acrobatic ability and talent for choreography. He does not seem to need it to either define himself to himself, or to prove his intensity and self-discipline to himself and others. Consequently, his fighting style is less introspective and more social. So: the above analogy. While cats are capable of forming great emotional bonds, they remain essentially solitary creatures, and appear to spend a lot of time thinking about themselves. Dogs are more social; they care more about connections and being loved than they do about looking cool and mysterious. Taken out of context, this could sound negative, but Jackie Chan is a dog.
The easiest way to compare Bruce and Jackie, though, has nothing to do with their fighting styles or bodies. Just look at the way they laugh. They have (had? how do you resolve verb tenses when one member of your party is alive, and one dead?) strikingly different senses of humor. Bruce would yelp and shriek and brag and smirk his way through a movie. He'd be angry, but smiling. He would be silly and playful, but not light-hearted. Jackie (at least back in the day) was mischievous, easy-going, without a care in the world. His characters would often play the fool in a situation, shrug, and pose as a provincial rube. He'd seem at home in a circus with the acrobats, or in a traveling carnival, or a troupe of comedians. Bruce never seemed like a fool, a jester, even when he was enjoying something silly. He seemed like he wanted to scream and kill somebody and then chuckle to the camera, his eyes narrowing at you slightly.