Well you might not like my opinion on this one but here it goes. Nerf bars are basically just steps to help get into a vehicle. The do not do well in harder off road situations. A friend of mine has them on his 97 TJ and the joke has always been " Well what are we going to do today finally rip those things from the frame?" Whenever he gets in a harder situation, it seems as if he is always hung up on them. Nerf bars are thin walled tube that act as a step. They do very little to protect the sides of your Jeep. There are plenty of products out there that do act as both a step and a guard.
Something like these on E-Bay are under $300 shipped. Maybe not the stongest but better than some nerf bars.