This is, quite simply my untrained opinion, and you're free to take it or leave it. I think you're overdoing the highlights, and don't have unified lighting for the whole model (for both your models).
For the red marine:
The OSL is way overdone. There's no way the light from the eyes would shine on the forehead, and the OSL light looks just as bright as the eyes themselves. You would probably get better results mixing the bronze and green before applying than layering the green over the bronze.
The white joint-things are way too bright. There's no way the joint on the back of the knee would be completely white, in shadow.
The weapons are a bit boring. They don't need to be completely metal! Try doing a few grays for everything except the working bits (barrel, bolts, teeth).
The scripty writing isn't fooling us at all. You don't need to actually write stuff, but I think short vertical lines or more variation in height would be better than long horizontal lines. I believe there is a tutorial around here somewhere.
You're going to hear this until you finally give in. The bases really need to be much better, and you might even be hurting your score over a plain base. Those rocks actually look a bit like gravel (minus the white/black) or coal, and have their place, but not covering the base.
Librarian:
I agree that this mini looks better, but you've still got some of the same things going on. Obviously base. The lighting seems completely random, at times contradictory. I'm not a fan of edge highlighting like that, but to each his own. The tops of the thighs look especially over-highlighted. You could probably go darker with the blues, as it seems to jump from blue to black.
I do think you should be looking at minis which are significantly higher score, rather than close, if you want to improve. Here are a few random ones, which show shading, more interesting weapons, and unified lighting source:
http://www.coolminiornot.com/281165
http://www.coolminiornot.com/281326
http://www.coolminiornot.com/281328