I like it, both model and texturing, but it can be improoved
first of all, most of what I'm saying depend from my tastes, so what I'd like to see may be different from what you'd like or what you have in mind
1- the overall contrast is too low (better the second version for this point)
2- I suggest to try a little more saturated red, a little more intense color
3-On the red areas (and types and numbers too) use a layer mask to give the impression of ruined paint (if you have the basic grey layer and then the layer with the red areas, you can add a layer mask on the red layer, and paint over the mask with the standard brush tools: as result the mask will hide some points of the red layer, with an effect like of ruined paint)
4-the grey area is a bit too monotone, too low contrast, and I think the plates should be little more squared; you should increase the plating effect, there are many ways:
-the way you already used, but increasing contrast
-bevel down the lines between the plates (at least some of them to give the inpression of a plating on more levels, this is a simple trick I use often)
-bevel up the plates (like venom did on the yellow police ranabout,and like

did on some tiles too, btw this works better when you have only few plates to bevel)
-add some variatons on some of the plates (some brighter some darker, some with a little different color, some other little rusty or dirty or scratched...)
5- add tech/mech elements, like holes in the plating around engines that lets you see parts of the engines, wires on the hull, etc etc
6- add dirty, scratches, rusty etc (this is handwork that takes sometime, but increase a lot the overall quality)
p.s.
this thing reminds me somehow a starwars transport, with some little modifications (different guns, a turret, different rear fins) it could work fine as a noncanon transport...can you post ome other shots plese?