My only experience is November 2001 to Sept. 30 of 2002 with Private Airport Security. From Oct. 2002 to Present with TSA.
No major differences in the two, if anything TSA seems to be a little worse, but both were bad.
At first, it seemed I was making a difference but within a few months knew I wasn't. The security in place really doesnt give you a chance to do so. The prodecures are just add ons of the old COG's that were in Checkpoints before 9/11.
But of course on 9/11 Airport Security didn't fail but was replaced anyway.