Almost perfect.

When using an already uploaded PDF in the Media Library, it’s a bit confusing with the plugin’s window floating over the WordPress media window, and you have to click “Insert” on the media window in the background to get the code and then click “Insert” again on the plugin window – but it works once you figure out what’s going on. Also I’d like to be able to customise the background colour in the iframe window around the outside of the PDF but at least it’s just a neutral grey.
Even with these niggles, this plugin is a gem!