I tried Scrivener, and quite liked it, but it didn't have styles, and I had issues with documents having inconsistent formatting for no readily apparent reason. I found lots of little irritations with Scrivener. Individually, they were tiny, so I kept with it, hoping that I'd get used to it, but in the end it was just too much and I gave up on it.
I've also written in a text editor called
Geany, using Markdown syntax for formatting. Using a text editor meant there were few distractions, which I liked. The side bar showed the headings, and so acted in a similar way to the navigator in LibreOffice and the binder in Scrivener.
I'm currently using LibreOffice. I've just installed the
writer2xhtml extension recommended by gmw, which resolves one issue that concerned me, since it means that I can easily export to a nicely formatted ePub for final editing in Sigil. I've been using OpenOffice since before v1, then switched to LibreOffice, so it's very familiar to me. I've recently discovered
EuroOffice, an Android app that allows me to edit .odt files on my phone, which I find occasionally useful. I've written a macro to provide me with a session word count, one of the things I liked about Scrivener that LibreOffice can't do out of the box.