Sharepoint is a product developed only for Internet Explorer, and all non-IE users would probably hate Sharepoint, as there are lots of incompatible functions missing out. Recently I found out that non-IE browsers such as Firefox and Chrome are not able to edit Office files directly when clicking on the file link. The data connectivity would not exist because the browser would simply download the file into local folder.
Thankfully, there is workaround for this. Simply get users to install this Firefox plugin: http://npopendocuments.codeplex.com which will fix this problem.