Have you tried pulling the bolt back and manually charging the gun? If it still does not it could be a bent elevator pinching the shell slightly. You could look at an unfired shell to see if it has been scratched.
What do you expect from the land of fruits and nuts. "Sporting purpose", I want the people that are saying that to find that for me anywhere in the Constitution.
To answer the op no they are not worth the extra money to me. I have personally never had a slam fire with any ar of mine. I have also not heard of anyone that I know having this problem. Could it happen? Sure, I guess, just always follow proper gun control and never point the muzzle at anything...
http://www.midwayusa.com/product/284427/leatherman-sidekick-multi-tool-stainless-steel?cm_mmc=pe_weekly-_-specials-_-specials_all_nonclickeremail_20150526_1-_-AdBlock02
Not bad and free shipping no tax.