Many people whose opinions I trust have lauded this book...

My first impressions? Oh look, a man alone in space doing Maths... it's Mark Watney...!

Is Weir's characterisation thin? Yes
Are his characters obvious Gary Stus? Undoubtedly.
Is Weir's decision to make a joke of his amnesiac scientist thinking he might be a paedophile hugely jarring? Yes
Is the premise - that a high school teacher is whisked away to do research on the hugely valuable, strictly finite quantity of the first ever alien life forms brought back by a probe - absurd? Yes - even with giving him a background in academia.

But also, it's all rather fun in a Marvel movie - switch your brain off and accept the ridiculousness - kind of way.