I enjoy a brown suit. I find it to be the versatile suit. You get both the formality of the suit silhouette and the easygoing mood from the brown shade. Clearly the versaility depends on your work. In some trades brown suits are no-go. If, however, you have the freedom to dress more or less as you please, the loosly defined brown suit seems to give more options that the fixed navy blue suit.
This article in a German magazine from around 1960, supports the perspective.,
Photo: The Journal of Style