I am a CSCS, and I think it's almost worthless unless you need it to get a S&C gig for training athletes. Very few CE's offered by the NSCA are worth anything to me.
I haven't looked much into it, but I've heard good things about NASM.
There's also an organization that is run out of the UK and recently arrived in the U.S. that is probably the best of them all in terms of content/knowledge base, but it's not yet well known in the states. I can't remember the name of it, but it's run out of a university that is well known for sports science.