Platinum all the way. The warmth of rose gold is nice, but in the long run I think the overall design motif of the watch calls for the colder, more technical-looking metal. Plus, I honestly feel that white metals are more versatile (personal preference). I love colored gold for certain watches (yellow gold for Breguet La Tradition, for example), but not in this particular case.
Nice photo comparison, Nicolas. Interesting post.
Cheers,
Daos