I have a couple CRT's with component outputs, so I tend to use RGB SCART to Component for my PC Engine/Turbo gaming. It even looks good with that connection on my el-cheapo LCD.
But I have noticed that even going the "standard" route with these consoles, the composite signal is still very acceptable. Even RF isn't terrible.
Compare that to composite out of, let's say, a Genesis console, and it's like day and night.