Open Office seems like an upgrade from Microsoft Office in that is easily compatible with different formats from different years and allows you to do things that are not as easy to do on Microsoft Office (ex. drawing). I like the fact that this program can be used by students at school or at home. The open-source license is a big plus.
Google docs also allows you to transfer many different types of documents. The share documents mode makes accessibility to others easy by having you create a list of users. This also prevents those who you do not want to view your product from doing so. I love that more than one person can make edits at the same time which can be critical when time is limited. Because this and Open Office are online they give users and advantage over Microsoft Office in that you do not have to e-mail a document to yourself to have access to it at home. I did not even think about the fact that online storage prevents loss of documents due to computer crashes. It is very easy to create a webpage link to your documents which is great if you want students to view your/their documents at school or at home.
I think these tools provide much greater capabilities than Microsoft Office. The one disadvantage I can see is that most people are more familiar with Microsoft Office since it has been in use for quite some time. Practice with Open Office and Google docs could offset this lack of experience with the programs.