I teach kids science, so reading THE MARTIAN was almost required reading. My other colleague liked it so much that he wanted to take our students to see it, saying it was an awesome depiction of why science is awesome.
And I agree.
The main character, Mark, has a billion problems in front of him, after getting left behind on Mars, and he has to use science in order to stay alive. A lot of science. A lot of trial and error. A lot of testing equipment.
The book is a bit on the clinical side. Mark has a quirky sense of humor, and that shines through now and then, but for the most part it's a report of what he's had to do to stay alive. As a teacher of science, I appreciated it. There were so many passages that I wanted to excerpt and make my students read because it was exactly what we are or will be learning in class. There was definitely tension when things went wrong, and I wanted to see how he would get out of it, but it was pretty straight-forward. I was waiting for them to pull a "The Mexican" and have there be actual martians or something, but no such luck.
The movie I really enjoyed (until one bit at the end). It had tension, the scenery was awesome, and in some parts had better characters than the book (Donald Glover as Rich Purnell was better than I imagined him). They didn't go into the science as much, and of course they had to skip some parts otherwise it'd be too long (though I really wanted to see all his trial and errors).
As for the end, they obviously Hollywood-ified it. The part about Iron Man is in the book, but it just felt sooo fake to me in the movie. So I enjoyed it up until that very end part.
So if you like science and suspense, definitely give it a try. But obvi read the book before you see the movie :)