I've installed 2 sets of mids, and one set of full, front to rear on 3 different XJ's. I have use TNT, RuffStuff, and Iron Rock Off Road. IMO, they're all about the same. Any manufacturer would be fine. There's another recent thread that lists the various ones.
I have long arms and rock rails on all 3 XJ's. So there's more strength to mount them. You get a better bumper tie in, too. It just gives the uni-body more strength. I don't see any downside.
For me, the biggest con was prepping the body for welding. What a pain in the ass! However, I think the benefits far outweigh the process of removing the paint and undercoating.
Would definitely do a full set again.