History Vs. Historical Fiction

I have been researching a historical event for some time now, and I think I can make a book of it. However, I was having trouble coming up with a way to do it: do I write a non-fiction book using truthful historical facts, or do I turn it into a historical novel where I can make a better, but untruthful, narrative? Guy Vanderhaeghe has an essay on how history and fiction fit together, which has given me more to think about.