Strongly red.

Red would set things off really beautifully, but I think a red binding would be too narrow to make a strong enough contrast. If you were adding a border, I'd say red. For binding, I vote for green.

I would say the dark green!

I'm partial to the red.

Red will make the red more dominant, green will blend in.

The frame around the medallion is red, and I think the binding would reflect this color and make the center pop

I would use the green that goes around your center medallion.

I think green. Red would make those red rectangles jump out much more, pulling the eye around.

If you really love red you could add red piping, or bind it in red, but overall I think green would be classy and wonderful with this lovely project.

Green for an olde worlde look, red for modern. Your quilt is beautiful!

Dark green. Definitely dark green