Woahh, Rainbow Man~!! They played that show in Hawaii in the 70s, right around the same time as Kikaida. Awesome theme songs, btw. I'll upload if I have the time.
IMO Rainbow Man began well but kind of petered out towards the end. Perhaps it ran for too long. There was a parallel plot line that involved his mother and younger sister, who had a polio-like disability.
FWIW, my user title is based on the subtitle for Rainbow Man.