On the question of whether to read the book or watch the adaptation when you only have time for one: my answer is almost always read the book, with one significant exception. If the adaptation is by a director whose work you know and whose sensibility is clearly in dialogue with the source, the adaptation is the better starting point because it gives you a reading — a prior interpretation — that you can then compare to the book.

Villeneuve's Dune is an example. Having seen the films first, I read the novel with his visual interpretation as a frame. The scenes that work differently in the novel — more interior, more dependent on the relationship between Paul's consciousness and the reader's — were clarified by the contrast.

The book first rule is a good default but it's not absolute.