Should I paint or stain a new fireplace mantle?

Will the existing fireplace color match the rest of your remodel?

What is the fireplace main background...is this just an all wood mantle surround or is it a wall of rock or brick? I would tend to go in the direction of matching the kitchen cabinets.

I would stain the same color as floors. It will pop from painted cabinets and tie in floor. Also consider going dark over light if it’s a natural fireplace. If it’s gas it won’t matter. Stain tends to be almost damage proof. Paint....not so much.

Gas fireplace place, not natural.

Staining the mantel may make it a final point,is that the look you want?