Probably you never bothered much about vertex painting because there the tools in Blender are to basic? This addon by Andrew Palmer will change your mind and makes working with vertex painting more useful. It has loads of options, really worth to try it out.
For me it is exactly that, never bothered about vertex painting and while looking around for addons I thought “Let give it a try”. (So I can write another article). It turns out another world opened. First of all there are loads of options to play with the colors, like adjusting colors on the fly. And secondly the power of the Vertex Color Master addon is that it can work with different channels (RGBA). So each channel can have it’s own data which you can then use for anything you need to mix.
It is not always the case that an addon comes with good documentation, but this addon has. See for documentation: Documentation Vertex Color Master. The documentation looks very decent.
The download link is as the documentation says. As usual I didn’t read the documentation properly and had to unzip the folder, find the right folder and zip that. So I didn’t try it the official way but I suppose the official way works better than my alternative. If not, let me know in the comments.