My opinions -
I like the dark colors you have chosen.
I like the tan for the light color.
For the center square - I think I would like a color that is between the bright rust and the dark brown you have chosen. Basically a browner rust. But of the two that you have shown, I thinkI like the dark brown better. I don't see any of that bright shade of rust in the center panel - and those bright squares would be the first thing I would see when looking at the quilt - and then I would wonder why that shade was chosen.