Ubuntu has many derivatives, some official (such as Kubuntu, Lubuntu and Xubuntu and many unofficial. However, unlike Fedora or openSUSE there is no 'pure' Gnome Shell 3 derivative of Ubuntu which you can simply download an install. Yes, you can add Gnome shell to your Unity desktop, but that's still not pure Gnome Shell 3 desktop.
So, I set out to find ways to install a pure Gnome Shell 3 desktop. It was far more easier than I expected and the beauty of the system is you don't get anything extra to bloat your system.
Yes, it needs some extra work, but then who cares. There is always a price to pay, and in the free software world that price is a little bit work -- which in the end makes you even more comfortable with GNU/Linux.
So, here is my unprofessional guide to installing Gubuntu (Gnome Shell+Buntu = Gubuntu). If there is already a pure Gnome Shell version of Ubuntu, please let me know.
Gnome Shell Vs Unity?
No, its not about which environment is better. As I have seen on our Facebook page, both have almost equal number of fans and user. Some love Unity and some prefer Gnome Shell 3. So, its more like I love red roses sometimes and you like white roses -- in the end its all roses. Same is the case with Gnome Shell 3 and Unity. In the end its all apt-get powered, Canonical backed Ubuntu.
So what we are going to do here is download a server version of Ubuntu (minimal, nos GUI) and then install Gnome on top of that. So, you will get a pure Gnome Desktop.
NOTE: It's very important that you are familiar with text-based installation of Ubuntu otherwise don't try this method.
Download the appropriate version of Ubuntu Server from here. Burn it on a CD or create a LiveUSB using Startup Disc creator. Insert the drive of the CD in your PC and boot into it. Make sure that your have LAN for Internet so that it is easier to install packages after installation.
Now follow the easy installation instructions and install the OS.
When it asks for 'select keyboard languages' select no and then select the appropriate language from the next window.
When it asks about 'selecting packages to install, just hit enter and and install the default system.
When it asks for choosing the partition where you want to install Ubuntu, select the partition carefully.
Once installed reboot your PC and you will be greeted by command prompt. Now run these commands
sudo apt-get update
sudo apt-get install gnome
it will download and install a lot of packages, let it run.
Once the installation of these packages is complete reboot the system and select Gnome (and NOT Ubuntu) from the login window. You now have a working Gnome Desktop. Since its Gnome Shell 3 desktop, you will need to install Gnome Tweak Tool. Since the tool is not in the Ubuntu repository you will have to add a PPA. Run this command.
sudo apt-add-repository ppa:gnome3-team/gnome3
Once added open Synaptic Package Manager and search and install gnome-tweak-tools. This tool will help you customize Gnome Shell.
Now, you have a pure Gnome Shell 3 Ubuntu running on your machine.
[Warning: 1. Make sure that you have LAN connection for the Internet or it will be a bit difficult to set network if you wireless behind password.
2. We assume that you have enough working knowledge of playing with command line and that you are well versed with installing Ubuntu using command line. If you are not certain, please don't try this at home. ]
Resources: If you face issues with network, please refer to this page: https://help.ubuntu.com/10.04/serverguide/C/network-configuration.html