Red v Blue seems to much like a video game... colors would most likely be affected by the intended use / combat situation etc. Awesome design though on the details, the color is almost a minor issue at that point.
I would suggest using the blue one with the light effects of the red one. the warm yellowish light effects on the red robot give the whole 'technical parts' like the exhaust pipe (?) at the head and the joints a more believable effect, while the color scheme of the blue robot just 'feels right'