I’m about to paint the trim outside the house. Just got new roof metal that is outlining the eaves. Will painting the metal give the home a better look or will it look better just leaving it silver?
Yes, you can paint this galvanized metal. If the metal flashing is visible then painting is a good idea. This will blend it with the trim color.
Usually this metal is allowed to "weather" for 3-4 weeks. This removes most of the residual oils from the manufacturing and shipping. In your case, it will require a quick washing. You can use an 1/8 cup of laundry detergent mixed with a couple gallons of warm water and rinse well with clean water. Or wipe it with a solvent, like acetone.
A good universal quick drying primer is needed. I would use an oil base, make sure it is compatible with galvanized metal.