I thought it was a decent movie (telling an appallingly indecent story), but it had nothing like the sheer raw emotional power of the source book. What is measured and carefully explained in the book is, in the film, glossed-over and presented as a neatly-packaged visual image.
Everything in the film is too clean, from the extraordinary hotel-standard bed linens seen in Solomon's original home to the fact the slaves are given nice metal plates and rather fine forks (Solomon tells you in the book that the only thing given to a slave is a rough blanket; gourds are the main receptacle, and if a slave earned any pennies the first thing they would buy would be a cooking knife). Everyone is made much wealthier than they were in reality; I'm not sure why.