It's so frustratingly untrue to the book! But quite watchable if you can manage to put that to one side.
In the series, Pip and Estella are both shown as pawns being forced to act against their will. The original story is so much more subtle. In the book, Pip is quite happy to leave the forge with barely a backwards glance as he is so sure he is destined for greater things. Estella has been deliberately ruined emotionally by Miss Havisham to the point where she quite willingly marries Drummle because she knows it will break her other suitors' hearts. She also intends to hurt Drummle, though in the end he is the one who physically abuses her and they are both unhappy in the marriage.
So the brutal and calculating partnership and manipulation of Jaggers and Miss Havisham in this series (which is a bit reminiscent of Dangerous Liaisons) is not quite right, and neither are Pip or Estella.
Pip in this version just seems thoroughly unlikeable and sulky, and I'm finding it hard to care much what happens to him.
I'm liking the acting and portrayals of Jagger, Estella and Havisham even though they aren't the characters from the book. I'll stick with it now I've got this far but suspect I'll be moaning about it to the end of the final episode!