Platinum in gray or the new black is more subdued and elegant. I would say it is at home in the office in a suit or while walking the dog in a t-shirt and jeans.
Rose is beautiful as well but a bit more formal and a bit more flashy for lack of a better term.
I own both and love them both. But I tend to wear the plat gray more, as it is more versatile.
Best of luck with your decision.
You can't really go wrong.
Nat