Can't tell you about NARS Madly -- but I love MAC Warm Soul. It is a bronzey colored brush with just a hint of shimmer. Looks very natural and warms up my skintone. Love it!
I just swatched Warm Soul yesterday and I own Madly. I think Madly is a cooler color. More on the taupe side with multi-colored pearl. WS is warmer and more golden.