What do you use to edit Microsoft Word documents (docx)?

LibreOffice is the replacement for OpenOffice and does the same job.

Abiword

Which is a part of gnome-office also supports docx format.

I can certify you that LibreOffice opens correctly Office 2007 Documents (docx) AND saves them correctly. I have tested till now a little over 50 documents which include tables, pictures, a lot of different margins, paragraphs, etc..

They open, read and save correctly. Tested with LibreOffice 3.3.2 and OpenOffice 3.3.0. With OpenOffice you will have a problem that text will move up or down and maybe even change the way they look. But in LibreOffice you will not.

This is a headache i can say goodbye at least for now.

Use the following to install the latest LibreOffice:

• How to install LibreOffice? (replacing OpenOffice.org)

NOTE - When you add the PPA of LibreOffice the option to remove OpenOffice will appear. I recommend you remove it since, trust me, it will be far better.

If you want to guarantee perfect compatibility with the docx format you could always run Office 2007 under Wine. Not the best for the open source ethos but it does work well if you already have a copy of office.