If you want to work on files with people (other than supported by google docs) you both need the desktop app installed. Far more people have the Dropbox desktop

If you want to work on files with people (other than supported by google docs) you both need the desktop app installed. Far more people have the Dropbox desktop app installed than Google drive. I find Dropbox websharing far easier, right-click share and it puts the link on the clipboard. Google drive makes you go through a dialog. Google Drive doesn't have history for non google doc files. We use it as a simple version control for all our documents.