I have installed Ubuntu 12.04 and later installed cinnamon.
I hade conflicts with nautilus being loaded for desktop instead of nemo and therefore not displaying my desktop icons. Therefore i uninstalled Unity and Nautilus.
sudo add-apt-repository ppa:gwendal-lebihan-dev/cinnamon-stable
sudo apt-get update
sudo apt-get install cinnamon
Then nemo was used as window manager for desktop.
I later installed ubuntu-desktop to get unity back and also nautilus.
Now in unity, nemo is being loaded as desktop window manager displaying icons. There is no issue with that expect i dont get the menu bar sort of options situated in the top panel for desktop in ubuntu. Other applications works fine with their options in the top bar.
I edited /usr/share/gnome-session/sessions/ubuntu.session as
which still uses nemo for desktop and opens nautilus filemanager as an window during login.
I also edited /usr/share/gnome-session/sessions/cinnamon.session as
which works alright using nemo for desktop.
I would like to try out other DE's like MATE,LXDE,XFCE etc..but each has different window managers and i would like to use each with their own window manager for desktop and also have all of them in my PC