Hey,
After using your Adam model for some time, I have a few comments:
First of all, the model is crafted with quality and looks asthetically pleasing during animation and rendering. For the price this model is a must have!

ONE problem I found with the model is the shooting animation.
In Adam's "ready" position (where he hold a pistol), his thumb is behind the pistol (or where the pistol would be). This, in real life, would break his thumb when using many pistols and makes many problems when trying to animate the model shooting.

You might want to fix this, however I quickly changed it myself.

I am planning on buying the zombie and other models from your site, great work!

-Mike