και η γνώμη ενός ...πιο ειδικού

Well, even if the general look is correct...maybe is too correct. The mud is well done, the effects, the details...but nothing catch the attention specially.
The final look is a little unform and flat, and this is maybe because the mud/dust is almost the same color than vehicle, and both (vehicle color and dust) is both matt.
There aren't any kind of contrast and the final result is less that could be with more contrast between the effects.
Example: a more light dust and more dark mud, using different colors that the base color of the vehicle could help. Also...if he paint the base color a little more SATIN , it will generate a nice contrast with the weathering effects.
The second point is more technical: the metal chips:
Even if them is nice...maybe is a little out of control in some areas. A recomendation is to be more prudent or carefully (more shy) when he apply the chips, in a way to control them more. Also, try to be more conservative with the chips size. In this small vehcile the chips seems bigger that surely is.
In resume:
Nice model but boring due the lack of natural contrasts in the weathring. No effects which catch the wather attention. But with minor correction the model could be great.
Thanks
MIG
Mig Jimenez