for those of you who watched the anime "Tengen Toppa Gurren Lagann"... the spiral power and the GL power seems to be fueled by the same thing, will power.
in Tengen Toppa Gurren Lagann the characters generate the will power through giant robots (forgot their name) making it spiral power, the GL generate the will power through their rings making it green power .
which do you thinks is, or present, stronger?
this topic might not be most accurate, but if there people who watched TTGl, they'll know what i'm taking about.
i vote spiral power!