I like the look of black anodized aluminum. A problem you will have is that the aluminum has gotten some salt imbedded in it and when it's anodized it will make a somewhat mottled look to the black. I anodized the aluminum disks on the top of the self tailing mechanism on my Barient winches.

They look fine and much better but they have small grey speckles all over them. Actually an interesting look but not a smooth black.

The company in Florida that did it said anodizing older salt infused aluminum just does that. Knowing that, I'd still go with black anodizing. Black against a Hatteras white painted boom is a good look.

The anodizing will look better a lot longer than paint or powder coating. At least from my past experience.