I like the colour scheme. You could possibly improve their appearance by giving them some definition - pick out the various armour parts with some black wash in "moving recesses" (i.e. joints). The plasma coils could also do with some "lighting effect" - in the least add a yellow highlight to the edges, wash with mid green, and add very fine highlights on the very edges.
Also, you might consider painting the gun muzzles black, or drilling them open - although it is extra work, I always do the latter nowadays, especially since boltguns have such a large surface to work on.
Finally, the helmet lenses could be picked out in a glowing yellow or red - yellow might be better, as it would not break up the colour scheme. I've found that painting in Marine helmet eyes does a lot to make the figure "pop".
That might all sound very negative. I think you've got some nice figures there, but at the moment, they look a little bit unfinished - it may, however, be the closeups, and they probably look better if seen at "gaming distance". Closeups are almost never favourable.