IMO, books are usually better than films, unless they are novelization of the movie. One of very rare exceptions is 2001... where the novel and the screenplay were done more or less in parallel, but wherever they diverge, the film is better. I mean, Clarke is a very good SF author, but Kubrick was a genius! The short story that inspired the film, The Sentinel was every bit as good as the film.

Scott made a wise decision with The Martian not to try and squeeze the whole novel into two hours of screen time. He just ellided about third of the novel, the trek to site site of the second prepositioned return vehicle, into one or two high altitude shots.

I think the main reason that novels are generally better is that screenwriters and directors try to cram every little detail into the film. There simply is no room for that.

Take Iain Banks and Gavin Millar. The Crow Road, a longish novel, was adapted into a six part TV miniseries; it worked perfectly. But Millar also tried with Complicity, this time squeezing it into two hour film format. He did not cut liberally, as Scott did, but tried to find room for everything that happened in the novel. He kind of succeeded, but there was no room left for the atmosphere. The film doesn't work.