I'm less than 100 pages from the end of the almost 900 page volume 2, so I can give you (and whoever else is curious) some quick impressions/summaries now.
Stephenson's Baroque Cycle series is 8 books that were either collected in 3 volumes or published separately depending on what edition you are getting.
Volume 1 (Quicksilver) covers the first three novels: Quicksilver, King of the Vagabonds, and Odalisque.
Quicksilver was an interesting way to start a sprawling series in that it has no real coherent plot. It focuses on the (fictional) Daniel Waterhouse, who is a puritan English scholar in the second half of the 17th century. The book follows his life for a decade or so from his time as a student at Cambridge college (alongside some of the most notable English men of that era) to his early career as a member of the Royal Society of London. It also has a few flash fowards to Daniel as an old man about 50 years later in Boston. You don't get any sort of coherent story. What you do get is a ton of history and historical fiction regarding science, mathematics, alchemy, puritanism and post-reformation England. Isaac Newton, John Wilkins, and Robert Hooke are major characters in the book, and Daniel is sort of presented as a behind the scenes assistant in a lot of their major work.
If you find Quicksilver a little dry, I would suggest powering through it, because it provides needed framing for future books. Things also take a major narrative change starting in book 2.
Book 2, King of the Vagabonds, introduces Half-cocked Jack Shaftoe and Eliza, two major characters and narrative view points in the remainder of the series. Jack is an English Vagabond and sometimes soldier. Book 2 gives you his background and picks up with him in Austria, where he meets Eliza. The book follows their journeys together, and has a much more coherent plot than the first novel. The setting is also very different than the first book. To start with, it mainly takes place in continental Europe, including Austria, Germany, the Netherlands and France. Second, Jack is a low class peasant (where Daniel's family was well off), so you get to see a different side of life in the late 17th century. Jack's a classic rogue, so expect more humor and action in this book.
Book 3: Book 3 continues with Eliza and returns to Daniel. After two books of set up, I think this is where things get really interesting (not that the last book was dull). Tons of political intrigue, some hints on where the series is actually going in the long run, and quite a bit of info on mathematics, economic theory/history, and cryptography if those topics interest you.
Volume 2 consists of 2 books, Bonanza and the Confusion, that have concurrent chronologies. You will switch between books as the timeline dictates if you get them as one volume. The Confusion continues the plot points going on in England, France and the Netherlands. Bonanza is a round the world adventure story full of pirates and more exotic African and Asian locales.
If you want a high stakes page turner, you won't get one in the Baroque cycle. While there are some terrific action sequences (and the writing is almost always witty), Stephenson doesn't shy away from very lengthy digressions on a large variety of topics. I find most of these digressions really interesting, but I think your enjoyment would depend on how much you like like history, science, economics, etc. If you have read Snow Crash, and enjoyed the data theory and Sumerian linguistics stuff, you will probably enjoy the digressions in these books as well.
