CC BY NC SA is more restrictive than the GPL, although this doesn't stop a lot of the GPL haters from fawning over it.
It's not an issue of freedom but of honesty. Many closed-source licenses are more honest than the GPL.
Whenever you see something licensed under CC-BY-NC-SA, you get to see
http://creativecommons.org/licenses/by-nc-sa/3.0/ which tells you exactly what you may and may not do.
Whenever a program is licensed under the GPL, you get to see a bunch of filthy lies, prefaced by the filthiest of all, that it "is intended to guarantee your freedom".
Then as soon as you misinterpret one of the thousands of edge cases that the GPL is designed to make happen as often as possible, hundreds of litigation-happy freetards blog up a smear campaign against you, ignoring any reasonable argument that your case does not violate the GPL, ignoring any offer to negotiate a compromise that would lead to stopping the perceived violation, accepting no other reparation than having you fully endorse their political agenda by GPLing all your code.
Even if you do understand the GPL, its proponents do not.
Even if you do something that is allowed, it is not worth risking your reputation, chances of employment, or business, just for the convenience of using GPL'd software.