I don't think the metallic would be too dark. Here's mine with Carrara. The coloring here is slightly off. IRL the metallic is slightly grayer and lighter. I LOVE my sink.

I would not order a sink until I had my stone reserved and decided. I almost bought a cafe brown silgranit because I *knew * I wanted Bianco Antico granite. Good thing I waited!

I won't comment on the staining of the lighter sinks as you can read dozens of threads here on the subject.

I agree with Breezy - wait until you have made your granite decision. However, know that Bianco Romano works with a lot of different siligranit colors. (I am assuming you are doing a Blanco siligranit sink based on the Metallic Grey comment but that might be incorrect.)

We have Colonial Cream granite which is kind of like Bianco Romano but with less black I'd say, and we did Biscotti. I was debating between it, Biscuit and Truffle and I opted for Biscotti because it wouldn't stand out as much as the truffle and it is darker than the biscuit so a little less likely to stain and show messes. I didn't want to draw attention to my sink, especially if it was dirty or full of dirty dishes, you know. Here are a few pics:

HTH.

I have biscuit and have had zero problems with staining. Any discolorations come right out with a spray of Clorox cleanup- no scrubbing necessary.