I'm not so sure that the 400-600 volt OD caps actually sound better, but with their thicker wires they might be a little easier to solder...and that's really marginal.
My preference is for the 716P, 200 volt Orange Drop caps for use in Fenders (I like Mallory 150's with humbuckers). The 200 volt cap is not nearly as large as the 600 volt, and so it's much easier to fit in the body cavity. The same is true proportionately with the 400 volt/200 volt comparison. As to the difference in tone? I think we might be splitting hairs here.