Picked up after viewing the spoiler laden trailer forthcoming film.

I suppose this would be classified as 'hard science', similar to the book I read earlier this year 'Seveneves'. Both books feature lengthy (likely accurate) procedural descriptions of various space engineering.
But where The Martian wins over Seveneves is it's judicious use of humour, breaking the tension enough to balance what would otherwise be a depressing deathmarch of a read. That and The Martian doesn't have a ridiculous third act featuring Mer-Men.

Enjoyed tremendously. Matt Damon is perfectly cast as the protagonist. Sympathised with his potato problem.