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'
I prefer the red. The blue of the armor plus the blue of the gun start to look similar as if they are meant to be part of a bad colour match up. The red makes the gun's energy light stand out as its own entity.
The blue feels a little bright, almost cartoonish - perhaps it could be a couple of shades darker.
And that... is my only criticism. I like the idea of different colours signifying different ranks, and the models and texturing themselves are absolutely impeccable. I love the nearly cybersteam aesthetic you've got going here.