After many years of using power bait, I've been able to find 3-4 colors that work well for me.
First, the colors that do not work for me: blue, orange, dark green, and nightcrawler flavor.
The ones that work (in no particular order) best for me: chartreuse, rainbow, beige
The chartreuse is the one I use the most often. But, the best color I've ever used is the beige (brownish yellow--looks like cookie dough) color. It's amazing how few people use that color (it's actually a little bit softer texture than the other colors). Heck, I don't think I've ever seen people around me using it.