Green is definitely brighter than red, haven't tried blue. I still have 5 more unused packs of nocturnals and can't use them this fall because two of the states I'm hunting don't allow them by law. How lame is that?
Pink isn't bad either lol ... I got a couple packs in a trade and use them on some GTs All my x nock nockutrals are green an I like them best .
Green and red! Shoot red in the PM and green in the AM. Green is easier to see during daytime. Red is better at night. :p