Careful, Outlander is a serious cult, with fanatics. My wife is a card carrying member. My life goals center around occasionally being favourably compared to Jaime. This has its own set of rewards.
It has a strong appeal to "women of a particular age".
TV series is pretty good, but the books are amazing I will admit. The initial assumption is "yeah Harlequin romance", but no, it definitely is not. Writer is no slouch, and this isn't some bodice-ripper trash. That said, there are some scenes that are.. well I will let you read them yourselves.
No coincidence G.R.R. Martin and D.Gabaldon are such good friends.