I agree with Chrome Molly...and I think it really boils down to a rider's individual preference rather than any sort of objective reality. Tires truly do make all the difference...the same bike can ride quite differently with different tires. I know I don't like ultra light wheels, especially on descents...I like a heavier wheel (particularly with a lighter frame) because I think it's more balanced. I have no scientific explanation, it's just something I've found, over time, that I like.

To make your informal study more accurate, wouldn't we also want to mention frame size? I think the greater flex in a larger frame would as relevant, or more relevant, than weight.