Yes you can adjust and correct the curves. You have to finish the curves first, then you can move them and move the nodes or even add or delet the nodes. This can be done with the points at the start also. 

Distortion of the mesh is mainly caused by not using enough nodes but there is a bit of a problem in the mirroring but if you have P7, it is a matter of using the morph brush set to soften.

I don't know how anyone can say this is a waste of money for the price and what it gives you to work with. Sure it's not FaceGen, but it is only about a 20th the price. The interface could do with some work.

As I stated earlier, there is a learning curve and not a very hard one at that. Do I think it's perfect, NO, not even close. Do I think it has it's use as another tool to help get the end results of what I'm doing, YES.