I think it's more like, going from left to right would be light-recon, light-medium, and medium-heavy. I say this because the first on the left practically has no armor except the chest and back platting along with the half the legs and arms, as for the middle it has more protection than the first, but not enough to consider it completely a medium armor class, and then the last has more then the previous as it now has mostly full body armor but leaves the pulvic area still a high vulnerable spot. Artwork is great and a nice interesting desigh in the armor as well, I like shoulder.
So when she gets the medium armor her arms become completely robotic? and her feet do when she gets the heavy armor? I think you need to consider that the person needs to fit into the armor you design for them instead of the armor changing them. Just a observation.
Reminds me an incredible lot of the new angular armour designs in Mass Effect 2, and might I say you've done a terrific job of conceptualising the sci-fi look of the armour whilst delivering it in a practical package. Even the girl's hair looks mildly practical.