Fiction, regarding both reading and writing.
Reading about true historical events is much less exciting in my opinion because chances are you already know the story and how it ends. Unless there are some fictional elements thrown in, in which case it becomes fiction. Based on true events, yes, but still fiction.
Writing about true historical events is much more work and much less fun. You have to research everything and stick to so many rules, imagination is barely necessary because you won't have an opportunity to implement it anyway. Unless there are some fictional elements thrown in, in which case... well, I already said that. I'm downright allergic to that because of the many boring papers I had to write for university.
My only exception when it comes to this is astronomy. I've read many non-fictional books about it, mostly from Stephen Hawking and similar scientists, but never read a single novel or watched a single movie (like Star Wars, the ignorance of which makes me uneducated in some people's eyes). I don't think there's anything more interesting than the space we all live in, and no novel or movie or other fictional story will ever make it more exciting than it already is.