The floating balls between the body parts look like cop outs, there has got to be something better you can put there.
Also I would increase the size of the lower torso piece, make it more technical looking, that piece looks like it should be the 'core' of the guys body but currently it looks like a piece of old fashioned pottery. The upper body needs to have more of a 'back' from this perspective at least it looks like its cut off at an angle across his back and it just looks wierd.
Give him more sharp edges, a robotic hero needs to look high tech and metallic. That guy is so smooth he looks like he is made of cloth, especially his arms and legs. Also as everyone else has pointed out he needs a better colour scheme. Blue is a great colour for super heroes (Im guessing this guy isnt a villain? If he is change his colour, blue isnt very villainous XD) but it needs to be more varied, just chuck in little spots of other colours in there, personally I think some green would work great but hey thats up to you.
I spend way too much time on graphics boards, sorry for the long boring CC, =P.
