Mm, it is a very different style from SVSSS. Very different tone too. I haven't read the NiF novel so I don't know how it compares but if the novel is very, very similar to the drama, then I'll say that it's also quite different in that NiF is tight, focuses mainly on the palace scheming/politicking and the cause-effect timeline is shorter.

I am incredibly biased for Devil Venerable, so my answer is Devil Venerable.