There are strategies that advertisers and promoters follow in order to convey their objective. A simple one being that the color red is inviting, stopping, and attractive to the eye. I'd suggest googling the effects of color on people if you're interested.
Regarding your question, maybe a contrast of colors might be more effective, it's all subjective unless you have statistics to back you up.
Depending on what you're trying to convey it will relate to the colors and styles you use. 'Good,' channel art won't = subs/views, but it is a good way to summarize your entire channel in a quick and pleasing way.