Safari: Works fine for this site.
Firefox: You must click on the grey fat line representing a Quicktime playbar. Firefox then ask permission to use the Quicktime plugin. Very annoying...Firefox also wants to download ALL data before you can start to play content. Gives the impression that things don´t work, but they do. Be patient.
Google Chrome: Acts pretty much like Firefox.
Opera: Does not work in the latest version. Does not give the play controls for QT.