is a good book. period. It's a quick read, and it's hard to put down; the epistolary format works well for moving along a plot that could easily get bogged down in details. The main character is likable and funny, and he reminds me quite a bit of a few "characters" I know IRL.
I'm probably not going to see the movie, since one of the aspects of the novel that I found most appealing was its lack of excessive sensationalism, sentimentalism, or politicizing. Sure, there were exciting bits, scary bits, and humans being humans, but Andy Weir let those things remain in the background. He let a good story be a good story and just that; in the past years I've come to doubt that moviemakers are capable of that sort of restraint, and so I'll stay away.
So, maybe it's not a five-star all-time favorite, but it's definitely a good and admirable read.