Same with me. I'm usually on Mac, and don't have MS Word, so I used Open Office. But I think there are still inconsistencies between OO and Word. And I heard that the Lulu print process doesn't particularly like Macs and PDF files, so I transferred it to PC, and then PDF'd it from there.
Normally, I write with "Bean" http://www.bean-osx.com/Bean.html
. It's less 'heavy' than OO (i.e. loads and works quicker), and it does just about everything I need it to. And it has a live word count, which is great, and what a lot of free word processors don't have.
TBH, I don't see the need for any 'home formatting' to ebook standard. I'm making everything available via Smashwords and Kindle, which do the formatting for you. And printing via Lulu needs a PDF.