A few years ago I read the book, on the one hand I thought it a real page-turner, but also a bit shallow and rather poorly written. I had the same feelings about this series. You keep watching because there are so many twists and turns and every episode ends with yet another unexpected cliffhanger. But as to the core of the story, i.e. the fatal love between young and (not so) innocent Nola and much older, handsome Harry Quebert, it impressed me as if that part of the screenplay was written by a teenage girl with some overwrought romantic fantasies: the way these two rather improbable lovers act and talk when they're together is so cloyingly sweet it makes your teeth ache. In fact, the whole story is made up of improbabilities, coincidences, and almost gothic circumstances, like mysterious disfigured men, multiple personality disorders, corrupt and murderous policemen, arson, etcetera, it's frankly a bit too much of everything.
Most of the acting is fine, with Patrick Dempsey as the main character, although in my opinion he didn't get enough room to really shine. Kristine Froseth made Nola more annoying than sweet. My favorite actor was Ben Schnetzer, I didn't know him before, he's very natural and convincing (and looks really awesome!).
All in all: involving but also a bit disappointing.