I like dark blue or green on man. And black has special place in my heart. Least color, I don't really know. For me I don't think men should not wear shiny colors. If he likes to wear , and suits on him so why not? I like any color on him, as long as he is happy with it.
I myself wear navy, dark forest greens, maroon or dark reds, black, white, grey, dark blue, brown and the cream color as these colors can interchange and look good together easily. I also wear various Irish flat caps in dark brown and black or dark green sometimes navy. I have a black formal jacket and pants that look nice as well as a proper vintage brown and grey three piece suit I usually wear a matching fedora with my suit.