I love it as it keeps all my research, plan, character notes, chapter summaries, scenes in one space and only a single click away. I put each scene in it's own section so editing and cross-referencing is very easy. I love it, actually!
I didn't start using it till the fifth (my current) draft but found it a useful exercise to transfer all the research documents, character notes docs, chapter scenes (copy & pasted every single one into Scrivener!) before I began the fifth edit. Has made the edit much easier, from a technical and organsational perspective. Just don't get too hung up on the software and what you can do with it - the actual writing comes first!
Scrivener is amazing. I write historical fiction as well and find it invaluable for keeping myself organised as I have copious amounts of notes and research going on all the time. It's especially good for me as I tend to have three or four projects on the go at the same time so it helps me keep them all sorted.