Stability of word processors - for writers

Hi I've just leapt into the world of Mac and need a stable word processor for writing long documents (40-80000 words). I also need the ability to share files with windows users as well as import out of Scrivener, etc, to a word based format without loss of formatting. I don't want to run Windows through Parallels or Bootcamp if I don't have to. I've considered just getting Office for Mac but I was wondering how stable programs like Open Office and Libre Office are for longer documents. :)