Interesting... My mom seems perfectly happy with LibreOffice. I also set her up with Gmail, so she can view the PowerPoint files without launching LO.
Also need to make sure to explain about file formats, or chances are pretty good that they'll try to send a LibreOffice file to a MS Office user.
I remember Office 2007's ODT support being rather poor, too. Most documents I tried to put through it only came through with minimal formatting preserved.
2007 did do fairly poorly from what I remember as well. 2010 though is much better; I go back and forth between those fairly regularly. Fonts are obviously an issue, and complex formatting isn't quite right all of the time, but each suite seems to open most of the other's file types fairly well.