Excellent trick showing us Andrew on Webupd8 to find out if we can run U using Compiz on our computer.
If you are a user of Ubuntu 11.04 y 11.10, open a terminal and type:
/usr/lib/nux/unity_support_test -p
And if they get in "Unity 3D supported" un "Yes" then they can use it. I leave you the image of how this operation would look.
Also another option would be see if you Hardware is certified by Canonical.