Now that I've finished the book, I wanted to weigh in again on how the ingredients writers choose to put into their stories can affect readers. For one thing, although Outlander might not be a typical romance novel, it does include a lot of fairly explicit sex. I'm not against sex in stories; I've certainly thrown in my fair share of sex scenes in my own books. But my feeling is that sex scenes are just like every other scene in the book; they need to either advance the plot, or reveal something about the characters— and I don't mean revealing his or her physical attributes. One sex scene being explicit could tell us something about the characters— how comfortable they are with their bodies, how much passion one character feels for the other— but, to me, repeating explicit scenes over and over just make the book longer for no good reason. In Outlander, the two main characters are supposed to be unable to keep their hands off each other, so there were numerous references to sex; sometimes it was a discrete one-sentence reference to what was going on, and I was fine with that, but when it got to the who-was-putting-what-where stage, I tended to skip over those bits.
The other thing in this book that turned me off was the explicit violence. I don't mind the fights— slashing and stabbing, a bout of fisticuffs, even gun play, can add action— but one character torturing another is not something I want to see spelled out. Because Outlander is told from Clarie's point of view, the details of how Jamie is tortured by the villain could easily have been left out, but the author has him tell Claire every single hideous thing the man did to him. Euuw. I skipped over a lot of that, too.
What I did like a lot was Gabaldon's immersive style. The story really did have a 17th feel to it, and she did a nice job with the large cast of supporting characters, keeping them all distinct and memorable. I'm not sorry I read the book, but I don't think I'll be looking up the next one. It's a flavorful series, but not just to my taste.
On the other hand, the books are obviously to lots of other folks' tastes because one of my commenters runs a reader forum dedicated to this series. I guess it's as true for books as for anything else: De gustibus non est disputandum.