Jason
Every render I do is iRay. The FaceGen figures will render fine in iray, but you can get even more realistic results by using Human Iray shader on your figure you can purchase from Daz. I would send you samples but there is no place here to add a attachment. Any further questions, feel free to ask.
Andy
If you're not using the Iran skin shaders from Human, try them. I've wasted a ton of money on different iray skin shaders and Human by far gives the best result.
Andy