Overall opinion: I liked it. 
 This book probably would've languished on some "maybe I'd like to read it one day" list, but then it was assigned as homework on the Hello Internet podcast (http://hellointernet.fm). Usually I either have already watched/listened/read something that was assigned as homework or I don't care so I just go ahead and listen, spoilers be damned. But since this one was a book that I might feasibly read, I decided to give it a go. And then power-read through it in a day so I could listen to the rest of the HI episode where they discussed it. 
 I was able to read it in a day mostly because it's an easy read. Mostly it's a page turner but also the writing is pretty perfunctory, and I totally started to skim the details. Did love the use of metric though! Frame of reference FTW!, sorry Americans. 
 (view spoiler)[I did find the journal bits started to drag and then I was really happy when the POV switched to NASA. I found I started to get more engaged with the story then as well. Even later in the book I think I looked forward to the NASA chapters or the remaining team members chapters (hide spoiler)] 
 The rest of this is mostly about the movie: I knew Matt Damon was going to be playing Mark Watney as I read it and I couldn't help thinking that Matt Damon was a weird choice. Watney comes off as way more dorky or nerdy than I picture Damon. Oh well. 
 So one thing that did strike me when reading the book was the "diversity" which I did appreciate and found pretty realistic considering the modern work environment of who would be working in a heavy STEM field. But then the trailer totally bugged me by having Mindy Park be white. This might be a massive assumption but with Park as the last name I pictured her as of Asian descent (specifically Korean). I also thought casting Chiwetel Ejiofor as Venkat Kapoor was a little weird...but I do quite like Chiwetel Ejiofor as an actor, so... 
 Another thing that I found out after the fact was that the novel was originally written as a serialized piece of work. That helped put some context to the flow of the novel.