I've been using ObjectDock for a few weeks now on both my old i7-920 PC and my new i7-4770K one with a clean install of Windows 8 Pro.

In both I have ObjectDock set so that it doesn't appear on top of every window I open and that works most of the time. Occasionally it doesn't though with maximised windows such as those of a browser and I have to minimize then maximize the window I have open in, say, Firefox v22.0 in order to get its window to appear on top of ObjectDock. Just clicking inside the browser window does push ObjectDock into the background.

It's only a minor issue but it can sometimes be a little annoying when it doesn't behave as it is supposed to (i.e. stay in the background when I open an app with a fullscreen window).