It's really good in the way that the best cheeseburger in town is really good. There are snobbish reasons to dislike it, but it is very good at being what it is. It's a superhero story but instead of magical powers and bad guys, it's a nerd being somewhat implausibly good at solving problems in a sci-fi context.
That is a good explanation. I loved Hail Mary, but it's cheeseburger sci-fi. A lot of fun, an easy read, very enjoyable. It's not Michelin Star material, but even Gordon Ramsey eats at Burger King sometimes.
If you enjoyed The Martian (book or film), then this is just more of the same.