But before I buy it… Is it possible to use all of the animations on a custom model which is rigged with bones? Will the animations apply to my model without any problems? Or how do I prepare my models to be used with this system?
Yes you can use any model that is mecanim compatible. Several have done it in the thread for it. Actually most of your questions have been answered in that thread. I would suggest reading through the thread for the Character System and ask in there or can send a pm to Robin. He is very helpful in answering any questions you might have.
Sorry the thread is here http://forum.unity3d.com/threads/143609-Character-System
Is was buried.