The Positive Feedback article linked by Sergs is discussing a VdH Colibri XGW with a long cantilever. After the article was written the Colibri was sent back to the factory and converted to a XPW with the current style shorter cantilever. The change in sound from G to P was very noticeable. Working on aural memory since A-B comparisons were not possible, the P sounds smoother, more refined with slightly better detail. The changes were only positive. No negatives were noted.
The downside mechanically is that gold is more malleable than platinum. Thus, gold does not suffer metal fatigue as rapidly as copper or platinum. Copper and platinum corrode, gold does not. There is no such thing as a free lunch.
If you have the bucks I would buy the platinum.