At the behest of many many people I finally read The Martian. I saw the movie twice in theatres so there weren't a lot of surprises in the book for me. I think the biggest surprise was how similar it was to the movie. Some people had told me the book is way better, but actually I found them to be pretty similar. That is to say they're both super fun and entertaining.
The coolest thing about the movie (to me) is how well it captures the tone of the book. Everything happening is super serious and tense, but the main character's sense of humour helps smooth it all over. The balance between tension and humour is what makes both the book and movie so enjoyable.
I certainly recommend the book, particularly to enjoy during a relaxing vacation like I did.