Seriously, I don't think there is. I think it's personal preference. Different buggies will excel in different areas. I've seen light weight buggies do some cool things, and I've seen heavy rigs do cool things. It all comes down to what you like and what you have.
One big factor I think a lot of people overlook is familiarity. People that have their rigs for years and know how they work and what to expect. These guys usually are dialed in and can outdrive high dollar rigs all day long. This coming from a guy that hasn't had the same rig for more than 2 years in a row.
Just thinking out loud here.
Good points, but I still stand on my optimum theory. But that optimum point is still in relation to what your goal is and the type of vehicle you are building.
I forget to factor in seat time... that's a very good point.