I think that under the right circumstances, coordinating colors can look very good. For instance, my family tartan (Graham of Menteith) in the weathered colorway is composed of olive greens and browns that look very nice with a brown tweed jacket, brown or olive hose, and brown leather accessories. Not particularly flamboyant, but the combination gives a composed look. Personally, I'd go for the brown tweed jacket with burgundy hose and tie. A tattersall shirt would break things up nicely. If I were looking for a semiformal or formal kilt ensemble, I'd opt for the modern and/or ancient colorways, which in my case, are composed of dark blues and greens. In that case, I think coordinating colors can wind up looking a little too monochrome and drab, so reds and yellows might be the way I'd go. Ultimately, I think it's up to the individual to decide what they think looks the best. If you like the way it looks on you, that's really all that matters.