The book started its own genre: the techno-thriller, and ever since, Crichton has been its favorite son. Andromeda deserves a good reputation, although Crichton explains without a pang of guilt that his editor at the time had him rewrite and rewrite it til he got it right. It explains why his later books might be so painfully blocky in the sentence department.
But he is a writer. Who else goes to medical school, but chooses scifi over medicine? Only one who has this particular disease known only to Writers. No one said that all talents are equal, but all writers are fruit of the same tree. And this is a clever book, working on several conceits. It treats the story like a report, complete with data sheets, detailed explanation of processes, and a complete bibliography, giving it the stain of authority. It opens like a Dickens story. At a certain point, it starts to read like a Vernian travelogue. He packs each chapter with gobs of creative detail, which you can tell he just loves to write. And it works. It is a very good story.
For writers, the basics of scifi run a story, not necessarily the execution. Also, good, moving chapters with lots of scientific detail and insight, as well as a joy in the details, insight into the human condition. There is very little fat in this writing. Given that, a lot can be forgiven... in this story’s case. I’m still not all that sure about Timeline!