Just a quick update: if you want all the changes in the new Gloobus Preview we were telling you about a few days ago, you can now install it via Gloobus PPA:
sudo add-apt-repository ppa:gloobus-dev/gloobus-preview
sudo apt-get update && sudo apt-get install gloobus-preview
If you have Nautilus Elementary PPA added, you can also install Gloobus Preview from that PPA!