Rated 3 out of 5 stars
Not sure why but other file types (like .doc) do indeed appear not to work. I get a message on google docs page that this type of file is not supported.
I don't know if that is a bug or not.
Also... would be more helpful if I did not need to search in context menu. Perhaps a popup to choose to preview or bypass. Or even optional setup to just use the extension as default behavior.