Honestly, I didn't finish the book. It's not that I don't appreciate 800 pages of a well-researched story, but there was a point, maybe half way through, where the characters became kind of offensive. The stereotypes of certain people in this book are unbearable (and this is right after I finished reading John Steinbeck's East of Eden, so you know which character I'm talking about). Also the linguistic skills given to Jamie is downright unbelievable. I can understand his knowledge of french and other european languages, but Mandarin Chinese? Eye-roll. I spent a year in China and can't even translate children's television shows.
Let's not forget he also LIES about significant things in his life to the woman he says he loves, and she doesn't seem to freakin mind. Frank's transgressions, to me, seem pretty mild compared to Jaime's, but look who she's allowing to tear her clothes off anyway.
Plot-wise, make sure you are ready for anything. Whatever preposterous scenario you can think of, it's probably in this book.
I thought the first book in the series (Outlander) was okay verging towards good, and the second book as well. Can't say the same about this one, though. Don't think reading the rest of the series would be worth my time, and will stick to Wikipedia descriptions if I ever get curious.