OFC Gamma Ray is the least Power Metal band. Gamma Ray it's like blending Helloween and Pet Shop Boys. Still, a lot of albums from GR surpass Helloween. Yes, even the Keeper one.
I think there's a noticeable difference from the block of 'Heading for Tomorrow' until 'Insanity...' and 'The Land of the Free'.
Then there's a pure power metal band.
Just a personal bit -- Gamma Ray's "Real World" "got me", or "clicked" at some (rather dark) point of my life, and made me look on life's complicated absurdities from a bit different - lighter - angle. If anything, I am grateful for that.