Which Lights Render Color Best?

Short answer (in order): The Sun, Tungsten, Some LEDs, Plasma, Fluorescent. This piece put together by Film Gear is one of the best practical comparisons I've seen on the subject:

https://vimeo.com/videogear/cri-video-lights

The practical implications of using a light source that has rendering issues is a lot of extra time in post trying to fix the problem or possibly not being able to achieve the look you want.