The actors they've chosen have all been superb in my opinion, but the directing and screenplays have been pretty downhill after Chris Colombus dropped off.
I already figured out how the 6th and 7th movies are going to be directed. The 6th movie is where Harry and Ron are struggling to take the Ring to Mount Doom, and the 7th is when Harry manages to throw it down the ventilation shaft of the Death Star.
On topic:
I have no complaints about the books, except I was hoping that we'd hear more about the Mirror of Erised.