That's a tough one. In my considered opinion I already train with the current "big name" in the style. He's an excellent teacher. We've worked together for so long that he knows exactly how to motivate me and get the material across. And he's so far ahead of where I am that it's not like I'd be able to learn more with someone else.
Maybe the putative founder of the system had the Super Special Mojo. Maybe even with the gap between cultures he could transmit it better. I have my doubts.
The question as phrased leaves a couple important things unspoken. It assumes that you can identify a single founder. I'm not sure that's correct in most cases. Helio Gracie took Ju Jitsu in some very interesting directions and put his personal stamp on it. But he built on what he learned from Meada-Sensei who was a student of Kano-Sensei who drew on old Ju Jitsu and brought it into the modern world. Parker's Kenpo is clearly a first cousin to Kajukenbo and the general martial arts environment of mid-20th century Oahu. And those are styles with clear defineable roots. Where do you draw the line?
What happens when you move into a culture whose martial arts family tree more closely resembles a mangrove swamp? My current practice is from Indonesia where syncretism is a defining characteristic of the national character. The martial arts draw from every foreigner who got in a fight with a local which includes Chinese, Indians, Dutchmen, Englishmen, Portugese, Japanese, Arabs, Persians and the inhabitants of thousands of islands. Even narrowing it down to Western Java all the styles mix, match, draw and borrow from each other. Saying that one person founded the particular style I do is sort of arbitrary.
My Unholy Trinity of Real Martial Arts Motivations - Legitimacy, Mystery and Specialness - comes into play here. By studying with The Source you're supposedly learning the best material from the best teacher. You've got the Legitimacy of being near the originator which means it's pure and unsullied. And you've got Specialness going big time. That assumes that the putative founder is also the best teacher, something which often isn't true. Lots of these guys could fight but couldn't teach. Or they had students whose skill and understanding surpassed their own. Or what they started evolved into something better than what they created. All are possible.
To my way of thinking they are the sign of a healthy, vital martial art. If students never go beyond their teachers the art will inevitably degenerate. 80 percent of 80 percent of 80 percent leads to the thin end of nothing whittled down to a point in a fairly short time. If the art doesn't change and improve over time it will not be able to deal with current conditions and will become a ritualized club increasingly irrelevant to the students' lives.
So would I rather study with my teacher or the founder? The answer to that is I'd like to understand what the founder was trying to get at. But I'd prefer to study with the teacher who can best help me advance my skill and understanding regardless of when and where he or she lived.