The reception to Quicksilver was generally positive. Some reviewers found the length cumbersome; however, others found the length impressive in its quality and entertainment value. Paul Boutin at Slate Magazine comments that Quicksilver offers an insight into how advanced and complicated science was during the age of "alchemists and microscope-makers"; and that the scientists of the period were "the forerunners of the biotech and nanotech researchers who are today's IT Geeks". Entertainment Weekly rates Quicksilver an A-, stating that the book "makes you ponder concepts and theories you initially thought you'll never understand". The critic finds a parallel between Stephenson's approach and a passage from the book describing an effort to put "all human knowledge ... in a vast Encyclopedia that will be a sort of machine, not only for finding old knowledge but for making new".
The Independent places emphasis on the comparisons between the story that evolves in Quicksilver and Stephenson's earlier novel Cryptonomicon, with the former "shaping up to be a far more impressive literary endeavour than most so-called 'serious' fiction. And it ends on a hell of a cliffhanger. No scholarly, and intellectually provocative, historical novel has been this much fun since The Name of the Rose". Patrick Ness considers Quicksilver to be "entertaining over an impossible distance. This isn't a book; it's a place to move into and raise a family." His review focuses on the scope of the material and humour inherent in Quicksilver. Mark Sanderson calls the novel an "astonishing achievement", and compares Quicksilver to "Thomas Pynchon's Mason & Dixon and Lawrence Norfolk's Lempriere's Dictionary." Although full of historical description and incredibly lengthy, Quicksilver is noticeably full of what Sanderson called "more sex and violence ... than any Tarantino movie". Stephenson balances his desire to respect the period with a need to develop a novel which entertains modern readers. In The Guardian, Steven Poole commented that 'Quicksilver was: "A great fantastical boiling pot of theories about science, money, war and much else, by turns broadly picaresque and microscopically technical, sometimes over-dense and sometimes too sketchy, flawed but unarguably magnificent, Quicksilver is something like a Restoration-era Gravity's Rainbow."
Polly Shulman of The New York Times finds Quicksilver hard to follow and amazingly complex but a good read. However she notes that the complicated and clunky dialogue between the characters is a distraction. She thinks a full appreciation of the work is only possible within the context of the remaining novels of The Baroque Cycle, and compares the novel to works by Dorothy Dunnett, William Gibson and Bruce Sterling, calling it "history-of-science fiction". In the post-publication review for The New York Times, Edward Rothstein remarks that the scope of the novel is at times detrimental: "Unfortunately, in this novelistic cauldron it can sometimes seem as if mercury's vapors had overtaken the author himself, as if every detail he had learned had to be anxiously crammed into his text, while still leaving the boundaries between fact and invention ambiguous". He considers the novel to be an "experiment in progress", although the historical background is compelling.
Deborah Friedell disliked Quicksilver. She mentions Stephenson's poor writing and his lack of knowledge of the literary tradition, which she considers to be because "the greatest influences upon Stephenson's work have been comic books and cartoons". She dislikes his use of anachronism, his failure to be literary and his general approach to historical fiction. She writes of Stephenson and the reviewers who reviewed the work in a positive manner:
Stephenson is decidedly not a prodigy; but his babe-in-the-woods routine has proved irresistible for some, who are hailing his seemingly innate ability to meld the products of exhaustive historical research with what they see as a brilliant, idiosyncratic sense of humor and adventure. Time's critic has declared that Stephenson has a "once-in-a-generation gift", and that Quicksilver "will defy any category, genre, precedent or label—except for genius". This is promotional copy disguised as literary criticism. There is nothing category-defying about this ridiculous book.
From the foreign press, the review in the Frankfurter Allgemeine points out the historical period of Quicksilver is one of the birth of science which corresponds with a period of language shift as English became the language of science. Moreover, the review focuses on Leibniz's principles of mathematics which Stephenson claims established the framework for modern computing.