my thoughts are for hunting, I prefer a color I don't encounter in nature as much... lime green leaves are more common than glowing red, & thus the red offers me a less confusing sight picture...
personally I think the yellow / orange rods that came with the set I bought, are even brighter than the green, if brightness was a main concern...
BTW... STEVIE... I have the same SDM sight on the front of my S&W 610 ( so far the only one I didn't have to make a sight, to get one tall enough to work with my Williams fiber optic ghost rings, that I mounted on the rear of all these )