When installing Compiz from the Software Center, it will use its own gnome window decorator, meaning that the title bars may vanish on the first start without further configuration and if enabling the window decoration, the default blue theme will be used.
I would advise to install it this way if not wanting to add any additional PPAs:
Deactivate any installed compositing manager in the XFCE options by unticking "compositing" in the window management settings or by removing custom compositors such as Compton from the startup applications.
Make sure the video card driver is up-to-date.
Open a terminal and enter: sudo apt-get install compiz compiz-plugins compizconfig-settings-manager metacity dconf-tools (The Compiz-Plugins are also needed for additional functionality such as animations and the cube and Metacity will be used to enable the original XFCE "Greybird" theme, dconf-tools for setting it up.)
Press Alt+F2 and enter dconf-editor to open it, then change the "theme"-values to Greybirdin org\gnome\desktop\vm\preferences and org\gnome\metacity.
Open the Compiz Configuration from the regular XFCE-settings menu at the bottom under extras and at least enable the following options: Composite, Gnome Compatibility, OpenGL, Window Decoration, Move Window, Resize Window, Place Windows. Also make sure that four horizontal workspaces are enabled in the general settings when wanting to use the cube. To find out what plugins I could/should enable, I used the following sources: How To Set Up Compiz In Xubuntu,Compiz Fusion on Your Desktop: Howto Ubuntu (Video Series), Xubuntu + Compiz = Pretty pretty Xubuntu
Press Alt+F2 again and enter compiz --replace to find out if everything works correctly before adding it to the autostart applications or changing any statup system files. If there are any problems, a simple reboot will disable it again.
Unfortunately, with this process, Compiz will use the old original Greybird-theme for window decoration with small control buttons on the top left. I have not found out yet how to make it use the Default theme from XFCE 4.12 with the Windows 7 styled large buttons on the top right, but I acutally prefer this theme/layout, so I'm not too eager about changing this working setup right now. If someone has an idea about how to do this, maybe they can add it to the thread.