I'm a yellow gold guy in general - usually, everything else equal, I will prefer yg over ss, wg, or plat. However, for the 70s Ellipse family, I prefer the WG, which looks more "wearable" to me. The yellow gold versions look more art deco (which is cool too, and if you're looking for this style to the max, than maybe YG is better?) while the WG versions still embody the 70s perfectly but with a more modern aesthetic for today's fashion.
