Ultimately we'll let you be the judge, but here are a few facts to consider. Anytime you change the color of a product it has the potential to absorb or reflect a different amount of heat than it previously did. That's because different colored and textured surfaces reflect and absorb heat differently.
Do hard black pavement and fluffy green grass feel differently on your feet in the same sun light? They are both exposed to the same energy, but they are reacting to that energy very differently. The same is true of siding. Changing the color of your siding leaves the potential for changing how it reacts to the air temperature, the sunlight, and other energy. In addition to this important fact, vinyl siding has a very high rate of expansion and contraction. You'll notice in the photo below the visible overlap becomes far more prominent once the siding is painted.