Granted that everyone has different tastes, this somewhat-more-than-middle-aged ( I think, not sure what is currently considered "middle-aged") male enjoys the "Outlander" series so much that I've re-read it at least four times (except IMOHbee; once, so far), and I'm finding that Ms Gabaldon has "spoiled " me, for many other writers I use to enjoy. I find that she brings her characters ( mostly the main ones) so much "to life", that I now find many other writers too "two-dimensional", to enjoy reading.
As for her historical accuracy, I find she does a pretty good job, but more than that, she has stimulated me to learn even more about the historical periods and settings she writes about.
Finally, as for the TV series: first I haven't had TV for almost 30 years, plus, I am somewhat afraid to watch, for fear of having the novels "spoiled" for me, by the ( admittedly necessary) ' editing', required to reduce a substantial novel into a TV series.
Not sure if I'll succumb to the temptation to watch it ( somehow, not sure how).
Anyway, I find her writing immensely enjoyable; I'm "additicted", and am already Jonesing for the next book , probably 3 or 4 years away