At first blush, I would lean toward the black idea based on the mention of dark gray. However, I would honestly encourage you to take your sample tiles to your fixture showroom. I did this and layed them out with the different finishes I was considering…and took photos. Helped me finalize my decision.

(My bathroom was very light tile and marble countertop, and the Delta Venetian Bronze contrast was the ”pop” that won.)

To me the bronze is very traditional, while the black is mod/contemporary. I think the style of your home will tell you which you should use.

I agree that it is more a question of "style" rather than one clashing with gray flooring.

FWIW I have oil rubbed bronze and when I was looking I found that the actual finish varied somewhat with some basically looking very dark brown/almost black and some looking more "antique" looking with some coppery highlights peeking through.

Phyrich has a variety of finishes and you can take a look at what the faucets look like in various finishes on their site. They differentiate between Antique Bronze, Oil Rubbed Bronze and they have an Matte Black Finish

I got my bathroom fixtures from them with an Oil Rubbed Finish. Since I have copper accents and a traditional bathroom I asked them to do a finish that had slightly more copper peeking through. They are a smaller company located in Los Angeles and were easy to deal with.

Phyrich Faucets

I feel like gray goes with almost everything, and I agree that hardware choice is more about the style than the color of the metal. If you want modern, go with black. If you want more traditional, go with ORB.

check out this bronze faucet with grey backsplash. they look great together:

Brass/gold!!