You can toggle between Unity and other DE's ("Desktop Environments") you have. So you can try another DE, and if you don't like it, you can always go back to Unity. (Of course, if you remove Unity, it won't show up as one of your DE options.)
When you log-in, there will be a small circular symbol next to the password field (above and on the right). Click it, and it will give you choices of DE. Here's what it may look like, depending of course on what DE's you've installed/are on your system:
I agree with nosparks, the Mate DE is much better than Unity.
First you have to install the Mate repository. I prefer to edit the sources.list file directly. You have to add lines to this file as root of course.
So, the command I use is "sudo gedit /etc/apt/sources.list" (WITHOUT the quotes.)
Add these lines to the bottom of the file:
deb http://packages.mate-desktop.org/repo/ubuntu precise main
deb-src http://packages.mate-desktop.org/repo/ubuntu precise main
Now update the list:
sudo apt-get update
Now you need to install the authentication:
sudo apt-get install mate-archive-keyring
Update again: sudo apt-get update
Check your Software Sources GUI . . . the repository and the authentication should be added.
Now install the Mate DE:
sudo apt-get install mate-core
sudo apt-get install mate-desktop-environment
Now, log out and log back in.
Log out again. This time, before you log back in, click on that circular little symbol by the password field. Mate should show up. Select it then enter your password . . . you will start up in the Mate environment. Customize as you wish, and remember this is basically Gnome2, so you will have the capability to customize much more than you did with Unity (which is Gnome3).
Sometimes the Mate DE is cranky and doesn't show up right away. Log in and out a few times. If it still doesn't show up at login (clicking that circular symbol), then you might have to run your Update Manager. Install all things Mate.
Now you can toggle back and forth between Mate and any other DE in the list.
To check for sure whether or not you're in Mate, there should be an "About Mate" selection in your system menu WHEN you boot into Mate:
Change gears . . .
There is some advantage to using the "Classic (No effects)" DE, because IT uses Metacity as your windows manager, while Unity defaults to Compiz, a windows manager that often causes video troubles, depending on your card/chips. I THINK Mate also uses Metacity.
(I use Mate in 12.04 and have had no troubles with a cranky video card. Plus Mate is pretty slick. It's much like the old GNOME2 desktop that a lot of users prefer. Much more customizable than Unity.)
For using the "Classic (No effects)" DE, see http://ubuntuforums.org/showthread.php?t=1966370 . This is a VERY informative thread. I highly recommend reading through it.