Pros:

- facial animation and other things that need to be.
this is great pros compared to other replacer that no have even facial anim.

Cons:

- flashlight do not cast shadow from body.
- very bright fresnel highlight.

Conclusion:

Flashlight do not cast shadow from body, like in a Sheva replacer. :( 
However in Chris replacer is no such problem.
Was be cool if this can be fixed.
As well as in a Chris replacer, material of Isaac body have very high fresnel specularity.
Sheva and standart survivors no have a very much bright fresnel highlight.

ps
Metal plates on him chest, look like plastic, i think it probably, because their face have a simmilar smooth group.
In the Dead Space they look flat, if i remember correctly.

pps
Sorry if my english is bad