I am up to episode 14 of series 4, apparently, and the last 6 or so episodes have really taken off. I was surprised and impressed. Since Louis Litt became a stronger character and Mike's secret is out to many, I am even getting to like the dialogue style and Jessica.
Donna and Louis keep it interesting for me, they have many layers.
It's really coming good.
I hope they can keep a good story line going between the characters.