Metallics have a longer life span. Metallics match with everything, while pink is limited. I love pink, but I might not love it in a few years. I consider metallics to be neutrals. They will always fit into any wardrobe.
What do you mean by life span? The expandage of use? Or the life of the handbag? When it comes to expandage of use, I think the metallics are perfect for every season.. Whether it's summer or winter. Whereas for the pink, can be use for summer only (for my opinion.) about the life of the handbag.. Not much experience.. I still don't have pink and metallics EVER.. So I'm going to put some notes here once I get my first pink and first metallic! Hehe!