Let's start with getting terminology right. Gnome Shell, Unity and Cinnamon all run on top of GNOME 3. MATE is a fork of GNOME 2. So when you write that for Linux Mint 13 "there's no Gnome," that doesn't make much sense as there is GNOME all around
The GNOME developers abandoned GNOME 2 so it can't be offered as a desktop on Linux Mint any longer, but MATE continues to be maintained and developed by the MATE developers (http://mate-desktop.org/
) and so Linux Mint comes with MATE since version 12. If you want the GNOME as you knew it on Helena, then indeed Viking777 is right and MATE will offer you a very similar desktop.
If you meant "there's no Gnome Shell
", you can easily add Gnome Shell to your Linux Mint 13 Cinnamon installation by installing the packages gnome-shell and gnome-session. Then from the login screen you can choose to run Gnome Shell for your session. Development of the MGSE (Mint Gnome Shell Extensions) as were added to Gnome Shell on Linux Mint 12 has been dropped, with all effort having been shifted to development of Cinnamon.
Edit: MATE, Cinnamon or Gnome Shell, it remains a personal choice which one works best for your