I don't think The Martian and Three-Body should be compared. I think it's fair to say that The Martian is more 'hard sci-fi' in that the story is more grounded in what we know to be true. Three-Body has to invent some ideas in order to finish it's story.
That said, I overall enjoyed Three Body more. Even if it did push me into an existential crisis of some sort.
It caught my eye that you said 'book' rather than 'books'. You might not be aware Three Body is part of a trilogy? If you've not read The Dark Forest and Death's End, you are in for a real treat.