Honestly I found Hail Mary to be rather old fashioned, reminding me more of early Niven rather than The Martian. This isn't necessarily a bad thing; I enjoyed it! But he has quite a hill to climb to beat his first novel.
Agreed. I mentioned that it is 'imaginative and fun', but it is not the same style of "The Martian" which (in my opinion) had nearly perfect technical execution. I admit to having had some apprehension about a loved author's next effort (I'm looking at you, "Artemis" and "Armada"), but "Hail Mary" did not fulfill that dread for me. So... yay!